Protocol

This article is about the protocol for a stable release of Minecraft Java Edition (1.21.1, protocol 767). For the Java Edition pre-releases, see Pre-release protocol. For the incomplete Bedrock Edition docs, see Bedrock Protocol. For the old Pocket Edition, see Pocket Edition Protocol Documentation.

This page presents a dissection of the current Minecraft protocol.

If you're having trouble, check out the FAQ or ask for help in the IRC channel #mcdevs on irc.libera.chat (More Information).

Note: While you may use the contents of this page without restriction to create servers, clients, bots, etc; substantial reproductions of this page must be attributed IAW CC BY-SA 4.0.

The changes between versions may be viewed at Protocol History.

1 Definitions

1.1 Data types
1.2 Identifier
1.3 VarInt and VarLong
1.4 Position
1.5 Fixed-point numbers

1.6 Bit sets

1.6.1 BitSet
1.6.2 Fixed BitSet

2.1 Without compression
2.2 With compression

3.1 Clientbound

3.2 Serverbound

3.2.1 Handshake
3.2.2 Legacy Server List Ping

4.1 Clientbound

4.1.1 Status Response
4.1.2 Pong Response (status)

4.2.1 Status Request
4.2.2 Ping Request (status)

5.1 Clientbound

5.1.1 Disconnect (login)
5.1.2 Encryption Request
5.1.3 Login Success
5.1.4 Set Compression
5.1.5 Login Plugin Request
5.1.6 Cookie Request (login)

5.2.1 Login Start
5.2.2 Encryption Response
5.2.3 Login Plugin Response
5.2.4 Login Acknowledged
5.2.5 Cookie Response (login)

6.1 Clientbound

6.1.1 Cookie Request (configuration)
6.1.2 Clientbound Plugin Message (configuration)
6.1.3 Disconnect (configuration)
6.1.4 Finish Configuration
6.1.5 Clientbound Keep Alive (configuration)
6.1.6 Ping (configuration)
6.1.7 Reset Chat
6.1.8 Registry Data
6.1.9 Remove Resource Pack (configuration)
6.1.10 Add Resource Pack (configuration)
6.1.11 Store Cookie (configuration)
6.1.12 Transfer (configuration)
6.1.13 Feature Flags
6.1.14 Update Tags (configuration)
6.1.15 Clientbound Known Packs
6.1.16 Custom Report Details (configuration)
6.1.17 Server Links (configuration)

6.2.1 Client Information (configuration)
6.2.2 Cookie Response (configuration)
6.2.3 Serverbound Plugin Message (configuration)
6.2.4 Acknowledge Finish Configuration
6.2.5 Serverbound Keep Alive (configuration)
6.2.6 Pong (configuration)
6.2.7 Resource Pack Response (configuration)
6.2.8 Serverbound Known Packs

7.1 Clientbound

7.1.1 Bundle Delimiter
7.1.2 Spawn Entity
7.1.3 Spawn Experience Orb
7.1.4 Entity Animation
7.1.5 Award Statistics
7.1.6 Acknowledge Block Change
7.1.7 Set Block Destroy Stage
7.1.8 Block Entity Data
7.1.9 Block Action
7.1.10 Block Update
7.1.11 Boss Bar
7.1.12 Change Difficulty
7.1.13 Chunk Batch Finished
7.1.14 Chunk Batch Start
7.1.15 Chunk Biomes
7.1.16 Clear Titles
7.1.17 Command Suggestions Response
7.1.18 Commands
7.1.19 Close Container
7.1.20 Set Container Content
7.1.21 Set Container Property
7.1.22 Set Container Slot
7.1.23 Cookie Request (play)
7.1.24 Set Cooldown
7.1.25 Chat Suggestions
7.1.26 Clientbound Plugin Message (play)
7.1.27 Damage Event
7.1.28 Debug Sample
7.1.29 Delete Message
7.1.30 Disconnect (play)
7.1.31 Disguised Chat Message
7.1.32 Entity Event
7.1.33 Explosion
7.1.34 Unload Chunk
7.1.35 Game Event
7.1.36 Open Horse Screen
7.1.37 Hurt Animation
7.1.38 Initialize World Border
7.1.39 Clientbound Keep Alive (play)
7.1.40 Chunk Data and Update Light
7.1.41 World Event
7.1.42 Particle
7.1.43 Update Light
7.1.44 Login (play)
7.1.45 Map Data
7.1.46 Merchant Offers
7.1.47 Update Entity Position
7.1.48 Update Entity Position and Rotation
7.1.49 Update Entity Rotation
7.1.50 Move Vehicle
7.1.51 Open Book
7.1.52 Open Screen
7.1.53 Open Sign Editor
7.1.54 Ping (play)
7.1.55 Ping Response (play)
7.1.56 Place Ghost Recipe
7.1.57 Player Abilities (clientbound)
7.1.58 Player Chat Message
7.1.59 End Combat
7.1.60 Enter Combat
7.1.61 Combat Death
7.1.62 Player Info Remove
7.1.63 Player Info Update
7.1.64 Look At
7.1.65 Synchronize Player Position
7.1.66 Update Recipe Book
7.1.67 Remove Entities
7.1.68 Remove Entity Effect
7.1.69 Reset Score
7.1.70 Remove Resource Pack (play)
7.1.71 Add Resource Pack (play)
7.1.72 Respawn
7.1.73 Set Head Rotation
7.1.74 Update Section Blocks
7.1.75 Select Advancements Tab
7.1.76 Server Data
7.1.77 Set Action Bar Text
7.1.78 Set Border Center
7.1.79 Set Border Lerp Size
7.1.80 Set Border Size
7.1.81 Set Border Warning Delay
7.1.82 Set Border Warning Distance
7.1.83 Set Camera
7.1.84 Set Held Item (clientbound)
7.1.85 Set Center Chunk
7.1.86 Set Render Distance
7.1.87 Set Default Spawn Position
7.1.88 Display Objective
7.1.89 Set Entity Metadata
7.1.90 Link Entities
7.1.91 Set Entity Velocity
7.1.92 Set Equipment
7.1.93 Set Experience
7.1.94 Set Health
7.1.95 Update Objectives
7.1.96 Set Passengers
7.1.97 Update Teams
7.1.98 Update Score
7.1.99 Set Simulation Distance
7.1.100 Set Subtitle Text
7.1.101 Update Time
7.1.102 Set Title Text
7.1.103 Set Title Animation Times
7.1.104 Entity Sound Effect
7.1.105 Sound Effect
7.1.106 Start Configuration
7.1.107 Stop Sound
7.1.108 Store Cookie (play)
7.1.109 System Chat Message
7.1.110 Set Tab List Header And Footer
7.1.111 Tag Query Response
7.1.112 Pickup Item
7.1.113 Teleport Entity
7.1.114 Set Ticking State
7.1.115 Step Tick
7.1.116 Transfer (play)
7.1.117 Update Advancements
7.1.118 Update Attributes
7.1.119 Entity Effect
7.1.120 Update Recipes
7.1.121 Update Tags (play)
7.1.122 Projectile Power
7.1.123 Custom Report Details
7.1.124 Server Links

7.2.1 Confirm Teleportation
7.2.2 Query Block Entity Tag
7.2.3 Change Difficulty
7.2.4 Acknowledge Message
7.2.5 Chat Command
7.2.6 Signed Chat Command
7.2.7 Chat Message
7.2.8 Player Session
7.2.9 Chunk Batch Received
7.2.10 Client Status
7.2.11 Client Information (play)
7.2.12 Command Suggestions Request
7.2.13 Acknowledge Configuration
7.2.14 Click Container Button
7.2.15 Click Container
7.2.16 Close Container
7.2.17 Change Container Slot State
7.2.18 Cookie Response (play)
7.2.19 Serverbound Plugin Message (play)
7.2.20 Debug Sample Subscription
7.2.21 Edit Book
7.2.22 Query Entity Tag
7.2.23 Interact
7.2.24 Jigsaw Generate
7.2.25 Serverbound Keep Alive (play)
7.2.26 Lock Difficulty
7.2.27 Set Player Position
7.2.28 Set Player Position and Rotation
7.2.29 Set Player Rotation
7.2.30 Set Player On Ground
7.2.31 Move Vehicle
7.2.32 Paddle Boat
7.2.33 Pick Item
7.2.34 Ping Request (play)
7.2.35 Place Recipe
7.2.36 Player Abilities (serverbound)
7.2.37 Player Action
7.2.38 Player Command
7.2.39 Player Input
7.2.40 Pong (play)
7.2.41 Change Recipe Book Settings
7.2.42 Set Seen Recipe
7.2.43 Rename Item
7.2.44 Resource Pack Response (play)
7.2.45 Seen Advancements
7.2.46 Select Trade
7.2.47 Set Beacon Effect
7.2.48 Set Held Item (serverbound)
7.2.49 Program Command Block
7.2.50 Program Command Block Minecart
7.2.51 Set Creative Mode Slot
7.2.52 Program Jigsaw Block
7.2.53 Program Structure Block
7.2.54 Update Sign
7.2.55 Swing Arm
7.2.56 Teleport To Entity
7.2.57 Use Item On
7.2.58 Use Item

Definitions

The Minecraft server accepts connections from TCP clients and communicates with them using packets. A packet is a sequence of bytes sent over the TCP connection. The meaning of a packet depends both on its packet ID and the current state of the connection. The initial state of each connection is Handshaking, and state is switched using the packets Handshake and Login Success.

Data types

All data sent over the network (except for VarInt and VarLong) is big-endian, that is the bytes are sent from most significant byte to least significant byte. The majority of everyday computers are little-endian, therefore it may be necessary to change the endianness before sending data over the network.

As a String Tag: For components only containing text (no styling, no events etc.).
As a Compound Tag: Every other case.

Identifier

Identifiers are a namespaced location, in the form of minecraft:thing . If the namespace is not provided, it defaults to minecraft (i.e. thing is minecraft:thing ). Custom content should always be in its own namespace, not the default one. Both the namespace and value can use all lowercase alphanumeric characters (a-z and 0-9), dot ( . ), dash ( - ), and underscore ( _ ). In addition, values can use slash ( / ). The naming convention is lower_case_with_underscores . More information. For ease of determining whether a namespace or value is valid, here are regular expressions for each:

Namespace: [a-z0-9.-_]
Value: [a-z0-9.-_/]

VarInt and VarLong

Variable-length format such that smaller numbers use fewer bytes. These are very similar to Protocol Buffer Varints: the 7 least significant bits are used to encode the value and the most significant bit indicates whether there's another byte after it for the next part of the number. The least significant group is written first, followed by each of the more significant groups; thus, VarInts are effectively little endian (however, groups are 7 bits, not 8).

VarInts are never longer than 5 bytes, and VarLongs are never longer than 10 bytes. Within these limits, unnecessarily long encodings (e.g. 81 00 to encode 1) are allowed.

Pseudocode to read and write VarInts and VarLongs:

private static final int SEGMENT_BITS = 0x7F; private static final int CONTINUE_BIT = 0x80;

public int readVarInt()  int value = 0; int position = 0; byte currentByte; while (true)  currentByte = readByte(); value |= (currentByte & SEGMENT_BITS)  <position; if ((currentByte & CONTINUE_BIT) == 0) break; position += 7; if (position >= 32) throw new RuntimeException("VarInt is too big"); > return value; >

public long readVarLong()  long value = 0; int position = 0; byte currentByte; while (true)  currentByte = readByte(); value |= (long) (currentByte & SEGMENT_BITS)  <position; if ((currentByte & CONTINUE_BIT) == 0) break; position += 7; if (position >= 64) throw new RuntimeException("VarLong is too big"); > return value; >

public void writeVarInt(int value)  while (true)  if ((value & ~SEGMENT_BITS) == 0)  writeByte(value); return; > writeByte((value & SEGMENT_BITS) | CONTINUE_BIT); // Note: >>> means that the sign bit is shifted with the rest of the number rather than being left alone value >>>= 7; > >

public void writeVarLong(long value)  while (true)  if ((value & ~((long) SEGMENT_BITS)) == 0)  writeByte(value); return; > writeByte((value & SEGMENT_BITS) | CONTINUE_BIT); // Note: >>> means that the sign bit is shifted with the rest of the number rather than being left alone value >>>= 7; > >

Note Minecraft's VarInts are identical to LEB128 with the slight change of throwing a exception if it goes over a set amount of bytes.

Note that Minecraft's VarInts are not encoded using Protocol Buffers; it's just similar. If you try to use Protocol Buffers Varints with Minecraft's VarInts, you'll get incorrect results in some cases. The major differences:

Minecraft's VarInts are all signed, but do not use the ZigZag encoding. Protocol buffers have 3 types of Varints: uint32 (normal encoding, unsigned), sint32 (ZigZag encoding, signed), and int32 (normal encoding, signed). Minecraft's are the int32 variety. Because Minecraft uses the normal encoding instead of ZigZag encoding, negative values always use the maximum number of bytes.
Minecraft's VarInts are never longer than 5 bytes and its VarLongs will never be longer than 10 bytes, while Protocol Buffer Varints will always use 10 bytes when encoding negative numbers, even if it's an int32 .

Value	Hex bytes	Decimal bytes
0	0x00	0
1	0x01	1
2	0x02	2
127	0x7f	127
128	0x80 0x01	128 1
255	0xff 0x01	255 1
25565	0xdd 0xc7 0x01	221 199 1
2097151	0xff 0xff 0x7f	255 255 127
2147483647	0xff 0xff 0xff 0xff 0x07	255 255 255 255 7
-1	0xff 0xff 0xff 0xff 0x0f	255 255 255 255 15
-2147483648	0x80 0x80 0x80 0x80 0x08	128 128 128 128 8

Value	Hex bytes	Decimal bytes
0	0x00	0
1	0x01	1
2	0x02	2
127	0x7f	127
128	0x80 0x01	128 1
255	0xff 0x01	255 1
2147483647	0xff 0xff 0xff 0xff 0x07	255 255 255 255 7
9223372036854775807	0xff 0xff 0xff 0xff 0xff 0xff 0xff 0xff 0x7f	255 255 255 255 255 255 255 255 127
-1	0xff 0xff 0xff 0xff 0xff 0xff 0xff 0xff 0xff 0x01	255 255 255 255 255 255 255 255 255 1
-2147483648	0x80 0x80 0x80 0x80 0xf8 0xff 0xff 0xff 0xff 0x01	128 128 128 128 248 255 255 255 255 1
-9223372036854775808	0x80 0x80 0x80 0x80 0x80 0x80 0x80 0x80 0x80 0x01	128 128 128 128 128 128 128 128 128 1

Position

Note: What you are seeing here is the latest version of the Data types article, but the position type was different before 1.14.

64-bit value split into three signed integer parts:

x: 26 MSBs
z: 26 middle bits
y: 12 LSBs

For example, a 64-bit position can be broken down as follows:

Example value (big endian): 01000110000001110110001100 10110000010101101101001000 001100111111

The red value is the X coordinate, which is 18357644 in this example.
The blue value is the Z coordinate, which is -20882616 in this example.
The green value is the Y coordinate, which is 831 in this example.

Encoded as follows:

((x & 0x3FFFFFF)

val = read_long(); x = val >> 38; y = val > 52; z = val > 38;

Note: The above assumes that the right shift operator sign extends the value (this is called an arithmetic shift), so that the signedness of the coordinates is preserved. In many languages, this requires the integer type of val to be signed. In the absence of such an operator, the following may be useful:

if x >= 1 if y >= 1 if z >= 1

Fixed-point numbers

Some fields may be stored as fixed-point numbers, where a certain number of bits represent the signed integer part (number to the left of the decimal point) and the rest represent the fractional part (to the right). Floating point numbers (float and double), in contrast, keep the number itself (mantissa) in one chunk, while the location of the decimal point (exponent) is stored beside it. Essentially, while fixed-point numbers have lower range than floating point numbers, their fractional precision is greater for higher values.

Prior to version 1.9 a fixed-point format with 5 fraction bits and 27 integer bits was used to send entity positions to the client. Some uses of fixed point remain in modern versions, but they differ from that format.

Most programming languages lack support for fractional integers directly, but you can represent them as integers. The following C or Java-like pseudocode converts a double to a fixed-point integer with n fraction bits:

x_fixed = (int)(x_double * (1
x_double = (double)x_fixed / (1
Bit sets
The types BitSet and Fixed BitSet represent packed lists of bits. The Notchian implementation uses Java's BitSet class.
BitSet
Bit sets of type BitSet are prefixed by their length in longs.
Field Name Field Type Meaning
Length VarInt Number of longs in the following array. May be 0 (if no bits are set).
Data Array of Long A packed representation of the bit set as created by BitSet.toLongArray .
The i th bit is set when (Data[i / 64] & (1
Fixed BitSet
Bit sets of type Fixed BitSet (n) have a fixed length of n bits, encoded as ceil(n / 8) bytes. Note that this is different from BitSet, which uses longs.
Field Name Field Type Meaning
Data Byte Array (n) A packed representation of the bit set as created by BitSet.toByteArray , padded with zeroes at the end to fit the specified length.
Other definitions
Term Definition
Player When used in the singular, Player always refers to the client connected to the server.
Entity Entity refers to any item, player, mob, minecart or boat etc. See the Minecraft Wiki article for a full list.
EID An EID — or Entity ID — is a 4-byte sequence used to identify a specific entity. An entity's EID is unique on the entire server.
XYZ In this document, the axis names are the same as those shown in the debug screen (F3). Y points upwards, X points east, and Z points south.
Meter The meter is Minecraft's base unit of length, equal to the length of a vertex of a solid block. The term “block” may be used to mean “meter” or “cubic meter”.
Registry A table describing static, gameplay-related objects of some kind, such as the types of entities, block states or biomes. The entries of a registry are typically associated with textual or numeric identifiers, or both.
Minecraft has a unified registry system used to implement most of the registries, including blocks, items, entities, biomes and dimensions. These "ordinary" registries associate entries with both namespaced textual identifiers (see #Identifier), and signed (positive) 32-bit numeric identifiers. There is also a registry of registries listing all of the registries in the registry system. Some other registries, most notably the block state registry, are however implemented in a more ad-hoc fashion.
Some registries, such as biomes and dimensions, can be customized at runtime by the server (see Registry Data), while others, such as blocks, items and entities, are hardcoded. The contents of the hardcoded registries can be extracted via the built-in Data Generators system.
A current list of properties and state ID ranges is found on burger.
Alternatively, the vanilla server now includes an option to export the current block state ID mapping, by running java -DbundlerMainClass=net.minecraft.data.Main -jar minecraft_server.jar --reports . See Data Generators for more information.
Packet format
Packets cannot be larger than 2 21 − 1 or 2097151 bytes (the maximum that can be sent in a 3-byte VarInt). Moreover, the length field must not be longer than 3 bytes, even if the encoded value is within the limit. Unnecessarily long encodings at 3 bytes or below are still allowed. For compressed packets, this applies to the Packet Length field, i.e. the compressed length.
Without compression
Field Name Field Type Notes
Length VarInt Length of Packet ID + Data
Packet ID VarInt
Data Byte Array Depends on the connection state and packet ID, see the sections below
With compression
Once a Set Compression packet (with a non-negative threshold) is sent, zlib compression is enabled for all following packets. The format of a packet changes slightly to include the size of the uncompressed packet.
Present? Compressed? Field Name Field Type Notes
always No Packet Length VarInt Length of (Data Length) + length of compressed (Packet ID + Data)
if size >= threshold No Data Length VarInt Length of uncompressed (Packet ID + Data)
Yes Packet ID VarInt zlib compressed packet ID (see the sections below)
Data Byte Array zlib compressed packet data (see the sections below)
if size < threshold No Data Length VarInt 0 to indicate uncompressed
Packet ID VarInt packet ID (see the sections below)
Data Byte Array packet data (see the sections below)
For serverbound packets, the uncompressed length of (Packet ID + Data) must not be greater than 2 23 or 8388608 bytes. Not that a length equal to 2 23 is permitted, which differs from the compressed length limit. The Notchian client, on the other hand, has no limit for the uncompressed length of incoming compressed packets.
If the size of the buffer containing the packet data and ID (as a VarInt) is smaller than the threshold specified in the packet Set Compression. It will be sent as uncompressed. This is done by setting the data length as 0. (Comparable to sending a non-compressed format with an extra 0 between the length, and packet data).
If it's larger than or equal to the threshold, then it follows the regular compressed protocol format.
The Notchian server (but not client) rejects compressed packets smaller than the threshold. Uncompressed packets exceeding the threshold, however, are accepted.
Compression can be disabled by sending the packet Set Compression with a negative Threshold, or not sending the Set Compression packet at all.
Handshaking
Clientbound
There are no clientbound packets in the Handshaking state, since the protocol immediately switches to a different state after the client sends the first packet.
Serverbound
Handshake
This causes the server to switch into the target state.
Packet ID State Bound To Field Name Field Type Notes
0x00 Handshaking Server Protocol Version VarInt See protocol version numbers (currently 767 in Minecraft 1.21).
Server Address String (255) Hostname or IP, e.g. localhost or 127.0.0.1, that was used to connect. The Notchian server does not use this information. Note that SRV records are a simple redirect, e.g. if _minecraft._tcp.example.com points to mc.example.org, users connecting to example.com will provide example.org as server address in addition to connecting to it.
Server Port Unsigned Short Default is 25565. The Notchian server does not use this information.
Next State VarInt Enum 1 for Status, 2 for Login, 3 for Transfer.
Legacy Server List Ping
This packet uses a nonstandard format. It is never length-prefixed, and the packet ID is an Unsigned Byte instead of a VarInt.
While not technically part of the current protocol, legacy clients may send this packet to initiate Server List Ping, and modern servers should handle it correctly. The format of this packet is a remnant of the pre-Netty age, before the switch to Netty in 1.7 brought the standard format that is recognized now. This packet merely exists to inform legacy clients that they can't join our modern server.
Packet ID State Bound To Field Name Field Type Notes
0xFE Handshaking Server Payload Unsigned Byte always 1 ( 0x01 ).
See Server List Ping#1.6 for the details of the protocol that follows this packet.
Status
Main article: Server List Ping
Clientbound
Status Response
Packet ID State Bound To Field Name Field Type Notes
0x00 Status Client
JSON Response String (32767) See Server List Ping#Status Response; as with all strings this is prefixed by its length as a VarInt.
Pong Response (status)
Packet ID State Bound To Field Name Field Type Notes
0x01 Status Client Payload Long Should be the same as sent by the client.
Serverbound
Status Request
The status can only be requested once immediately after the handshake, before any ping. The server won't respond otherwise.
Packet ID State Bound To Field Name Field Type Notes
0x00 Status Server no fields
Ping Request (status)
Packet ID State Bound To Field Name Field Type Notes
0x01 Status Server Payload Long May be any number. Notchian clients use a system-dependent time value which is counted in milliseconds.
Login
The login process is as follows:

C→S: Handshake with Next State set to 2 (login)
C→S: Login Start
S→C: Encryption Request
Client auth (if enabled)
C→S: Encryption Response
Server auth (if enabled)
Both enable encryption
S→C: Set Compression (optional)
S→C: Login Success
C→S: Login Acknowledged

Set Compression, if present, must be sent before Login Success. Note that anything sent after Set Compression must use the Post Compression packet format.
Three modes of operation are possible depending on how the packets are sent:

Online-mode with encryption
Offline-mode with encryption
Offline-mode without encryption

For online-mode servers (the ones with authentication enabled), encryption is always mandatory, and the entire process described above needs to be followed.
For offline-mode servers (the ones with authentication disabled), encryption is optional, and part of the process can be skipped. In that case Login Start is directly followed by Login Success. The Notchian server only uses UUID v3 for offline player UUIDs, deriving it from the string OfflinePlayer: For example, Notch’s offline UUID would be chosen from the string OfflinePlayer:Notch . This is not a requirement however, the UUID can be set to anything.
As of 1.21, the Notchian server never uses encryption in offline mode.
Clientbound
Disconnect (login)
Packet ID State Bound To Field Name Field Type Notes
0x00 Login Client Reason JSON Text Component The reason why the player was disconnected.
Encryption Request
Packet ID State Bound To Field Name Field Type Notes
0x01 Login Client Server ID String (20) Appears to be empty.
Public Key Length VarInt Length of Public Key.
Public Key Byte Array The server's public key, in bytes.
Verify Token Length VarInt Length of Verify Token. Always 4 for Notchian servers.
Verify Token Byte Array A sequence of random bytes generated by the server.
Should authenticate Boolean Whether the client should attempt to authenticate through mojang servers.
Login Success
Packet ID State Bound To Field Name Field Type Notes
0x02 Login Client UUID UUID
Username String (16)
Number Of Properties VarInt Number of elements in the following array.
Property Name Array String (32767)
Value String (32767)
Is Signed Boolean
Signature Optional String (32767) Only if Is Signed is true.
Strict Error Handling Boolean Whether the client should immediately disconnect upon a packet processing error. The Notchian client silently ignores them when this flag is false.
This field was temporarily added in 1.20.5 as a way to aid modded servers with the transition to the new data pack & registry system, allowing them to tell the client to silently ignore packets containing inconsistent data. It will likely be removed soon, but it is still present as of version 1.21.1.
The Property field looks like response of Mojang API#UUID to Profile and Skin/Cape, except using the protocol format instead of JSON. That is, each player will usually have one property with Name being “textures” and Value being a base64-encoded JSON string, as documented at Mojang API#UUID to Profile and Skin/Cape. An empty properties array is also acceptable, and will cause clients to display the player with one of the two default skins depending their UUID (again, see the Mojang API page).
Set Compression
Enables compression. If compression is enabled, all following packets are encoded in the compressed packet format. Negative values will disable compression, meaning the packet format should remain in the uncompressed packet format. However, this packet is entirely optional, and if not sent, compression will also not be enabled (the notchian server does not send the packet when compression is disabled).
Packet ID State Bound To Field Name Field Type Notes
0x03 Login Client Threshold VarInt Maximum size of a packet before it is compressed.
Login Plugin Request
Used to implement a custom handshaking flow together with Login Plugin Response.
Unlike plugin messages in "play" mode, these messages follow a lock-step request/response scheme, where the client is expected to respond to a request indicating whether it understood. The notchian client always responds that it hasn't understood, and sends an empty payload.
Packet ID State Bound To Field Name Field Type Notes
0x04 Login Client Message ID VarInt Generated by the server - should be unique to the connection.
Channel Identifier Name of the plugin channel used to send the data.
Data Byte Array (1048576) Any data, depending on the channel. The length of this array must be inferred from the packet length.
In Notchian client, the maximum data length is 1048576 bytes.
Cookie Request (login)
Requests a cookie that was previously stored.
Packet ID State Bound To Field Name Field Type Notes
0x05 Login Client Key Identifier The identifier of the cookie.
Serverbound
Login Start
Packet ID State Bound To Field Name Field Type Notes
0x00 Login Server Name String (16) Player's Username.
Player UUID UUID The UUID of the player logging in. Unused by the Notchian server.
Encryption Response
Packet ID State Bound To Field Name Field Type Notes
0x01 Login Server Shared Secret Length VarInt Length of Shared Secret.
Shared Secret Byte Array Shared Secret value, encrypted with the server's public key.
Verify Token Length VarInt Length of Verify Token.
Verify Token Byte Array Verify Token value, encrypted with the same public key as the shared secret.
Login Plugin Response
Packet ID State Bound To Field Name Field Type Notes
0x02 Login Server Message ID VarInt Should match ID from server.
Successful Boolean true if the client understood the request, false otherwise. When false , no payload follows.
Data Optional Byte Array (1048576) Any data, depending on the channel. The length of this array must be inferred from the packet length.
In Notchian server, the maximum data length is 1048576 bytes.
Login Acknowledged
Acknowledgement to the Login Success packet sent by the server.
Packet ID State Bound To Field Name Field Type Notes
0x03 Login Server no fields
This packet switches the connection state to configuration.
Cookie Response (login)
Response to a Cookie Request (login) from the server. The Notchian server only accepts responses of up to 5 kiB in size.
Packet ID State Bound To Field Name Field Type Notes
0x04 Login Server Key Identifier The identifier of the cookie.
Has Payload Boolean The payload is only present if the cookie exists on the client.
Payload Length Optional VarInt Length of the following byte array.
Payload Optional Byte Array (5120) The data of the cookie, if any.
Configuration
Clientbound
Cookie Request (configuration)
Requests a cookie that was previously stored.
Packet ID State Bound To Field Name Field Type Notes
0x00 Configuration Client Key Identifier The identifier of the cookie.
Clientbound Plugin Message (configuration)
Main article: Plugin channels
Mods and plugins can use this to send their data. Minecraft itself uses several plugin channels. These internal channels are in the minecraft namespace.
More information on how it works on Dinnerbone's blog. More documentation about internal and popular registered channels are here.
Packet ID State Bound To Field Name Field Type Notes
0x01 Configuration Client Channel Identifier Name of the plugin channel used to send the data.
Data Byte Array (1048576) Any data. The length of this array must be inferred from the packet length.
In Notchian client, the maximum data length is 1048576 bytes.
Disconnect (configuration)
Packet ID State Bound To Field Name Field Type Notes
0x02 Configuration Client Reason Text Component The reason why the player was disconnected.
Finish Configuration
Sent by the server to notify the client that the configuration process has finished. The client answers with Acknowledge Finish Configuration whenever it is ready to continue.
Packet ID State Bound To Field Name Field Type Notes
0x03 Configuration Client no fields
This packet switches the connection state to play.
Clientbound Keep Alive (configuration)
The server will frequently send out a keep-alive, each containing a random ID. The client must respond with the same payload (see Serverbound Keep Alive). If the client does not respond to a Keep Alive packet within 15 seconds after it was sent, the server kicks the client. Vice versa, if the server does not send any keep-alives for 20 seconds, the client will disconnect and yields a "Timed out" exception.
The Notchian server uses a system-dependent time in milliseconds to generate the keep alive ID value.
Packet ID State Bound To Field Name Field Type Notes
0x04 Configuration Client Keep Alive ID Long
Ping (configuration)
Packet is not used by the Notchian server. When sent to the client, client responds with a Pong packet with the same id.
Packet ID State Bound To Field Name Field Type Notes
0x05 Configuration Client ID Int
Reset Chat
Packet ID State Bound To Field Name Field Type Notes
0x06 Configuration Client no fields
Registry Data
Represents certain registries that are sent from the server and are applied on the client.
Packet ID State Bound To Field Name Field Type Notes
0x07 Configuration Client
Registry ID Identifier
Entry Count VarInt Number of entries in the following array.
Entries Entry ID Array Identifier
Has Data Boolean Whether the entry has any data following.
Data NBT Entry data. Only present if Has Data is true.
Remove Resource Pack (configuration)
Packet ID State Bound To Field Name Field Type Notes
0x08 Configuration Client Has UUID Boolean Whether a specific resource pack should be removed, or all of them.
UUID Optional UUID The UUID of the resource pack to be removed. Only present if the previous field is true.
Add Resource Pack (configuration)
Packet ID State Bound To Field Name Field Type Notes
0x09 Configuration Client UUID UUID The unique identifier of the resource pack.
URL String (32767) The URL to the resource pack.
Hash String (40) A 40 character hexadecimal, case-insensitive SHA-1 hash of the resource pack file.
If it's not a 40 character hexadecimal string, the client will not use it for hash verification and likely waste bandwidth.
Forced Boolean The Notchian client will be forced to use the resource pack from the server. If they decline they will be kicked from the server.
Has Prompt Message Boolean Whether a custom message should be used on the resource pack prompt.
Prompt Message Optional Text Component This is shown in the prompt making the client accept or decline the resource pack. Only present if the previous field is true.
Store Cookie (configuration)
Stores some arbitrary data on the client, which persists between server transfers. The Notchian client only accepts cookies of up to 5 kiB in size.
Packet ID State Bound To Field Name Field Type Notes
0x0A Configuration Client Key Identifier The identifier of the cookie.
Payload Length VarInt Length of the following byte array.
Payload Byte Array (5120) The data of the cookie.
Transfer (configuration)
Notifies the client that it should transfer to the given server. Cookies previously stored are preserved between server transfers.
Packet ID State Bound To Field Name Field Type Notes
0x0B Configuration Client Host String The hostname or IP of the server.
Port VarInt The port of the server.
Feature Flags
Used to enable and disable features, generally experimental ones, on the client.
Packet ID State Bound To Field Name Field Type Notes
0x0C Configuration Client Total Features VarInt Number of features that appear in the array below.
Feature Flags Array of Identifier
As of 1.21, the following feature flags are available:

minecraft:vanilla - enables vanilla features
minecraft:bundle - enables support for the bundle
minecraft:trade_rebalance - enables support for the rebalanced villager trades

Update Tags (configuration)
Packet ID State Bound To Field Name Field Type Notes
0x0D Configuration Client Length of the array VarInt
Array of tags Registry Array Identifier Registry identifier (Vanilla expects tags for the registries minecraft:block , minecraft:item , minecraft:fluid , minecraft:entity_type , and minecraft:game_event )
Array of Tag (See below)
Tag arrays look like:
Field Name Field Type Notes
Length VarInt Number of elements in the following array
Tags Tag name Array Identifier
Count VarInt Number of elements in the following array
Entries Array of VarInt Numeric IDs of the given type (block, item, etc.). This list replaces the previous list of IDs for the given tag. If some preexisting tags are left unmentioned, a warning is printed.
See Tag on the Minecraft Wiki for more information, including a list of vanilla tags.
Clientbound Known Packs
Informs the client of which data packs are present on the server. The client is expected to respond with its own Serverbound Known Packs packet. The Notchian server does not continue with Configuration until it receives a response.
The Notchian client requires the minecraft:core pack with version 1.21 for a normal login sequence. This packet must be sent before the Registry Data packets.
Packet ID State Bound To Field Name Field Type Notes
0x0E Configuration Client Known Pack Count VarInt The number of known packs in the following array.
Known Packs Namespace Array String
ID String
Version String
Custom Report Details (configuration)
Contains a list of key-value text entries that are included in any crash or disconnection report generated during connection to the server.
Packet ID State Bound To Field Name Field Type Notes
0x0F Configuration Client Details Count VarInt (32) The number of details in the following array.
Details Title Array String (128)
Description String (4096)
Server Links (configuration)
This packet contains a list of links that the Notchian client will display in the menu available from the pause menu. Link labels can be built-in or custom (i.e., any text).
Packet ID State Bound To Field Name Field Type Notes
0x10 Configuration Client Links Count VarInt The number of links in the following array.
Links Is built-in Array Boolean True if Label is an enum (built-in label), false if it's a text component (custom label).
Label VarInt Enum / Text Component See below.
URL String Valid URL.
ID Name Notes
0 Bug Report Displayed on connection error screen; included as a comment in the disconnection report.
1 Community Guidelines
2 Support
3 Status
4 Feedback
5 Community
6 Website
7 Forums
8 News
9 Announcements

Serverbound
Client Information (configuration)
Sent when the player connects, or when settings are changed.
Packet ID State Bound To Field Name Field Type Notes
0x00 Configuration Server Locale String (16) e.g. en_GB .
View Distance Byte Client-side render distance, in chunks.
Chat Mode VarInt Enum 0: enabled, 1: commands only, 2: hidden. See Chat#Client chat mode for more information.
Chat Colors Boolean “Colors” multiplayer setting. Can the chat be colored?
Displayed Skin Parts Unsigned Byte Bit mask, see below.
Main Hand VarInt Enum 0: Left, 1: Right.
Enable text filtering Boolean Enables filtering of text on signs and written book titles. Currently always false (i.e. the filtering is disabled)
Allow server listings Boolean Servers usually list online players, this option should let you not show up in that list.
Displayed Skin Parts flags:

Bit 0 (0x01): Cape enabled
Bit 1 (0x02): Jacket enabled
Bit 2 (0x04): Left Sleeve enabled
Bit 3 (0x08): Right Sleeve enabled
Bit 4 (0x10): Left Pants Leg enabled
Bit 5 (0x20): Right Pants Leg enabled
Bit 6 (0x40): Hat enabled

The most significant bit (bit 7, 0x80) appears to be unused.
Cookie Response (configuration)
Response to a Cookie Request (configuration) from the server. The Notchian server only accepts responses of up to 5 kiB in size.
Packet ID State Bound To Field Name Field Type Notes
0x01 Configuration Server Key Identifier The identifier of the cookie.
Has Payload Boolean The payload is only present if the cookie exists on the client.
Payload Length Optional VarInt Length of the following byte array.
Payload Optional Byte Array (5120) The data of the cookie, if any.
Serverbound Plugin Message (configuration)
Main article: Plugin channels
Mods and plugins can use this to send their data. Minecraft itself uses some plugin channels. These internal channels are in the minecraft namespace.
Note that the length of Data is known only from the packet length, since the packet has no length field of any kind.
Packet ID State Bound To Field Name Field Type Notes
0x02 Configuration Server Channel Identifier Name of the plugin channel used to send the data.
Data Byte Array (32767) Any data, depending on the channel. minecraft: channels are documented here. The length of this array must be inferred from the packet length.
In Notchian server, the maximum data length is 32767 bytes.
Acknowledge Finish Configuration
Sent by the client to notify the server that the configuration process has finished. It is sent in response to the server's Finish Configuration.
Packet ID State Bound To Field Name Field Type Notes
0x03 Configuration Server no fields
This packet switches the connection state to play.
Serverbound Keep Alive (configuration)
The server will frequently send out a keep-alive (see Clientbound Keep Alive), each containing a random ID. The client must respond with the same packet.
Packet ID State Bound To Field Name Field Type Notes
0x04 Configuration Server Keep Alive ID Long
Pong (configuration)
Response to the clientbound packet (Ping) with the same id.
Packet ID State Bound To Field Name Field Type Notes
0x05 Configuration Server ID Int id is the same as the ping packet
Resource Pack Response (configuration)
Packet ID State Bound To Field Name Field Type Notes
0x06 Configuration Server
UUID UUID The unique identifier of the resource pack received in the Add Resource Pack (configuration) request.
Result VarInt Enum Result ID (see below).
Result can be one of the following values:
ID Result
0 Successfully downloaded
1 Declined
2 Failed to download
3 Accepted
4 Downloaded
5 Invalid URL
6 Failed to reload
7 Discarded
Serverbound Known Packs
Informs the server of which data packs are present on the client. The client sends this in response to Clientbound Known Packs.
If the client specifies a pack in this packet, the server should omit its contained data from the Registry Data packet.
Packet ID State Bound To Field Name Field Type Notes
0x07 Configuration Server Known Pack Count VarInt The number of known packs in the following array.
Known Packs Namespace Array String
ID String
Version String
Play
Clientbound
Bundle Delimiter
The delimiter for a bundle of packets. When received, the client should store every subsequent packet it receives, and wait until another delimiter is received. Once that happens, the client is guaranteed to process every packet in the bundle on the same tick, and the client should stop storing packets.
As of 1.20.6, the Notchian server only uses this to ensure Spawn Entity and associated packets used to configure the entity happen on the same tick. Each entity gets a separate bundle.
The Notchian client doesn't allow more than 4096 packets in the same bundle.
Packet ID State Bound To Field Name Field Type Notes
0x00 Play Client no fields
Spawn Entity
Sent by the server when an entity (aside from Experince Orb) is created.
Packet ID State Bound To Field Name Field Type Notes
0x01 Play Client Entity ID VarInt A unique integer ID mostly used in the protocol to identify the entity.
Entity UUID UUID A unique identifier that is mostly used in persistence and places where the uniqueness matters more.
Type VarInt ID in the minecraft:entity_type registry (see "type" field in Entity metadata#Entities).
X Double
Y Double
Z Double
Pitch Angle To get the real pitch, you must divide this by (256.0F / 360.0F)
Yaw Angle To get the real yaw, you must divide this by (256.0F / 360.0F)
Head Yaw Angle Only used by living entities, where the head of the entity may differ from the general body rotation.
Data VarInt Meaning dependent on the value of the Type field, see Object Data for details.
Velocity X Short Same units as Set Entity Velocity.
Velocity Y Short
Velocity Z Short
The points listed below should be considered when this packet is used to spawn a player entity.
When in online mode , the UUIDs must be valid and have valid skin blobs. In offline mode, the Notchian server uses UUID v3 and chooses the player's UUID by using the String OfflinePlayer: , encoding it in UTF-8 (and case-sensitive), then processes it with UUID.nameUUIDFromBytes .
For NPCs UUID v2 should be used. Note:
i will never confirm this as a feature you know that :)
In an example UUID, xxxxxxxx-xxxx-Yxxx-xxxx-xxxxxxxxxxxx , the UUID version is specified by Y . So, for UUID v3, Y will always be 3 , and for UUID v2, Y will always be 2 .
Spawn Experience Orb
Spawns one or more experience orbs.
Packet ID State Bound To Field Name Field Type Notes
0x02 Play Client Entity ID VarInt
X Double
Y Double
Z Double
Count Short The amount of experience this orb will reward once collected.
Entity Animation
Sent whenever an entity should change animation.
Packet ID State Bound To Field Name Field Type Notes
0x03 Play Client Entity ID VarInt Player ID.
Animation Unsigned Byte Animation ID (see below).
Animation can be one of the following values:
ID Animation
0 Swing main arm
2 Leave bed
3 Swing offhand
4 Critical effect
5 Magic critical effect
Award Statistics
Sent as a response to Client Status (id 1). Will only send the changed values if previously requested.
Packet ID State Bound To Field Name Field Type Notes
0x04 Play Client Count VarInt Number of elements in the following array.
Statistic Category ID Array VarInt See below.
Statistic ID VarInt See below.
Value VarInt The amount to set it to.
Categories (these are namespaced, but with : replaced with . ):
Name ID Registry
minecraft.mined 0 Blocks
minecraft.crafted 1 Items
minecraft.used 2 Items
minecraft.broken 3 Items
minecraft.picked_up 4 Items
minecraft.dropped 5 Items
minecraft.killed 6 Entities
minecraft.killed_by 7 Entities
minecraft.custom 8 Custom
Blocks, Items, and Entities use block (not block state), item, and entity ids.
Custom has the following (unit only matters for clients):
Name ID Unit
minecraft.leave_game 0 None
minecraft.play_one_minute 1 Time
minecraft.time_since_death 2 Time
minecraft.time_since_rest 3 Time
minecraft.sneak_time 4 Time
minecraft.walk_one_cm 5 Distance
minecraft.crouch_one_cm 6 Distance
minecraft.sprint_one_cm 7 Distance
minecraft.walk_on_water_one_cm 8 Distance
minecraft.fall_one_cm 9 Distance
minecraft.climb_one_cm 10 Distance
minecraft.fly_one_cm 11 Distance
minecraft.walk_under_water_one_cm 12 Distance
minecraft.minecart_one_cm 13 Distance
minecraft.boat_one_cm 14 Distance
minecraft.pig_one_cm 15 Distance
minecraft.horse_one_cm 16 Distance
minecraft.aviate_one_cm 17 Distance
minecraft.swim_one_cm 18 Distance
minecraft.strider_one_cm 19 Distance
minecraft.jump 20 None
minecraft.drop 21 None
minecraft.damage_dealt 22 Damage
minecraft.damage_dealt_absorbed 23 Damage
minecraft.damage_dealt_resisted 24 Damage
minecraft.damage_taken 25 Damage
minecraft.damage_blocked_by_shield 26 Damage
minecraft.damage_absorbed 27 Damage
minecraft.damage_resisted 28 Damage
minecraft.deaths 29 None
minecraft.mob_kills 30 None
minecraft.animals_bred 31 None
minecraft.player_kills 32 None
minecraft.fish_caught 33 None
minecraft.talked_to_villager 34 None
minecraft.traded_with_villager 35 None
minecraft.eat_cake_slice 36 None
minecraft.fill_cauldron 37 None
minecraft.use_cauldron 38 None
minecraft.clean_armor 39 None
minecraft.clean_banner 40 None
minecraft.clean_shulker_box 41 None
minecraft.interact_with_brewingstand 42 None
minecraft.interact_with_beacon 43 None
minecraft.inspect_dropper 44 None
minecraft.inspect_hopper 45 None
minecraft.inspect_dispenser 46 None
minecraft.play_noteblock 47 None
minecraft.tune_noteblock 48 None
minecraft.pot_flower 49 None
minecraft.trigger_trapped_chest 50 None
minecraft.open_enderchest 51 None
minecraft.enchant_item 52 None
minecraft.play_record 53 None
minecraft.interact_with_furnace 54 None
minecraft.interact_with_crafting_table 55 None
minecraft.open_chest 56 None
minecraft.sleep_in_bed 57 None
minecraft.open_shulker_box 58 None
minecraft.open_barrel 59 None
minecraft.interact_with_blast_furnace 60 None
minecraft.interact_with_smoker 61 None
minecraft.interact_with_lectern 62 None
minecraft.interact_with_campfire 63 None
minecraft.interact_with_cartography_table 64 None
minecraft.interact_with_loom 65 None
minecraft.interact_with_stonecutter 66 None
minecraft.bell_ring 67 None
minecraft.raid_trigger 68 None
minecraft.raid_win 69 None
minecraft.interact_with_anvil 70 None
minecraft.interact_with_grindstone 71 None
minecraft.target_hit 72 None
minecraft.interact_with_smithing_table 73 None

None: just a normal number (formatted with 0 decimal places)
Damage: value is 10 times the normal amount
Distance: a distance in centimeters (hundredths of blocks)
Time: a time span in ticks

Acknowledge Block Change
Acknowledges a user-initiated block change. After receiving this packet, the client will display the block state sent by the server instead of the one predicted by the client.
Packet ID State Bound To Field Name Field Type Notes
0x05 Play Client Sequence ID VarInt Represents the sequence to acknowledge, this is used for properly syncing block changes to the client after interactions.
Set Block Destroy Stage
0–9 are the displayable destroy stages and each other number means that there is no animation on this coordinate.
Block break animations can still be applied on air; the animation will remain visible although there is no block being broken. However, if this is applied to a transparent block, odd graphical effects may happen, including water losing its transparency. (An effect similar to this can be seen in normal gameplay when breaking ice blocks)
If you need to display several break animations at the same time you have to give each of them a unique Entity ID. The entity ID does not need to correspond to an actual entity on the client. It is valid to use a randomly generated number.
Packet ID State Bound To Field Name Field Type Notes
0x06 Play Client Entity ID VarInt The ID of the entity breaking the block.
Location Position Block Position.
Destroy Stage Byte 0–9 to set it, any other value to remove it.
Block Entity Data
Sets the block entity associated with the block at the given location.
Packet ID State Bound To Field Name Field Type Notes
0x07 Play Client Location Position
Type VarInt The type of the block entity
NBT Data NBT Data to set. May be a TAG_END (0), in which case the block entity at the given location is removed (though this is not required since the client will remove the block entity automatically on chunk unload or block removal).
Block Action
This packet is used for a number of actions and animations performed by blocks, usually non-persistent. The client ignores the provided block type and instead uses the block state in their world.
See Block Actions for a list of values.
This packet uses a block ID from the minecraft:block registry, not a block state.
Packet ID State Bound To Field Name Field Type Notes
0x08 Play Client Location Position Block coordinates.
Action ID (Byte 1) Unsigned Byte Varies depending on block — see Block Actions.
Action Parameter (Byte 2) Unsigned Byte Varies depending on block — see Block Actions.
Block Type VarInt The block type ID for the block. This value is unused by the Notchian client, as it will infer the type of block based on the given position.
Block Update
Fired whenever a block is changed within the render distance.
Changing a block in a chunk that is not loaded is not a stable action. The Notchian client currently uses a shared empty chunk which is modified for all block changes in unloaded chunks; while in 1.9 this chunk never renders in older versions the changed block will appear in all copies of the empty chunk. Servers should avoid sending block changes in unloaded chunks and clients should ignore such packets.
Packet ID State Bound To Field Name Field Type Notes
0x09 Play Client Location Position Block Coordinates.
Block ID VarInt The new block state ID for the block as given in the block state registry.
Boss Bar
Packet ID State Bound To Field Name Field Type Notes
0x0A Play Client UUID UUID Unique ID for this bar.
Action VarInt Enum Determines the layout of the remaining packet.
Action Field Name
0: add Title Text Component
Health Float From 0 to 1. Values greater than 1 do not crash a Notchian client, and start rendering part of a second health bar at around 1.5.
Color VarInt Enum Color ID (see below).
Division VarInt Enum Type of division (see below).
Flags Unsigned Byte Bit mask. 0x1: should darken sky, 0x2: is dragon bar (used to play end music), 0x04: create fog (previously was also controlled by 0x02).
1: remove no fields no fields Removes this boss bar.
2: update health Health Float as above
3: update title Title Text Component
4: update style Color VarInt Enum Color ID (see below).
Dividers VarInt Enum as above
5: update flags Flags Unsigned Byte as above
ID Color
0 Pink
1 Blue
2 Red
3 Green
4 Yellow
5 Purple
6 White
ID Type of division
0 No division
1 6 notches
2 10 notches
3 12 notches
4 20 notches
Change Difficulty
Changes the difficulty setting in the client's option menu
Packet ID State Bound To Field Name Field Type Notes
0x0B Play Client Difficulty Unsigned Byte 0: peaceful, 1: easy, 2: normal, 3: hard.
Difficulty locked? Boolean
Chunk Batch Finished
Marks the end of a chunk batch. The Notchian client marks the time it receives this packet and calculates the elapsed duration since the beginning of the chunk batch. The server uses this duration and the batch size received in this packet to estimate the number of milliseconds elapsed per chunk received. This value is then used to calculate the desired number of chunks per tick through the formula 25 / millisPerChunk , which is reported to the server through Chunk Batch Received. This likely uses 25 instead of the normal tick duration of 50 so chunk processing will only use half of the client's and network's bandwidth.
The Notchian client uses the samples from the latest 15 batches to estimate the milliseconds per chunk number.
Packet ID State Bound To Field Name Field Type Notes
0x0C Play Client Batch size VarInt Number of chunks.
Chunk Batch Start
Marks the start of a chunk batch. The Notchian client marks and stores the time it receives this packet.
Packet ID State Bound To Field Name Field Type Notes
0x0D Play Client no fields
Chunk Biomes
Packet ID State Bound To Field Name Field Type Notes
0x0E Play Client
Number of chunks VarInt Number of elements in the following array
Chunk biome data Chunk Z Array Int Chunk coordinate (block coordinate divided by 16, rounded down)
Chunk X Int Chunk coordinate (block coordinate divided by 16, rounded down)
Size VarInt Size of Data in bytes
Data Byte Array Chunk data structure, with sections containing only the Biomes field
Note: The order of X and Z is inverted, because the client reads them as one big-endian Long, with Z being the upper 32 bits.
Clear Titles
Clear the client's current title information, with the option to also reset it.
Packet ID State Bound To Field Name Field Type Notes
0x0F Play Client Reset Boolean
Command Suggestions Response
The server responds with a list of auto-completions of the last word sent to it. In the case of regular chat, this is a player username. Command names and parameters are also supported. The client sorts these alphabetically before listing them.
Packet ID State Bound To Field Name Field Type Notes
0x10 Play Client
ID VarInt Transaction ID.
Start VarInt Start of the text to replace.
Length VarInt Length of the text to replace.
Count VarInt Number of elements in the following array.
Matches Match Array String (32767) One eligible value to insert, note that each command is sent separately instead of in a single string, hence the need for Count. Note that for instance this doesn't include a leading / on commands.
Has tooltip Boolean True if the following is present.
Tooltip Optional Text Component Tooltip to display; only present if previous boolean is true.
Commands
Lists all of the commands on the server, and how they are parsed.
This is a directed graph, with one root node. Each redirect or child node must refer only to nodes that have already been declared.
Packet ID State Bound To Field Name Field Type Notes
0x11 Play Client Count VarInt Number of elements in the following array.
Nodes Array of Node An array of nodes.
Root index VarInt Index of the root node in the previous array.
For more information on this packet, see the Command Data article.
Close Container
This packet is sent from the server to the client when a window is forcibly closed, such as when a chest is destroyed while it's open. The notchian client disregards the provided window ID and closes any active window.
Packet ID State Bound To Field Name Field Type Notes
0x12 Play Client Window ID Unsigned Byte This is the ID of the window that was closed. 0 for inventory.
Set Container Content

The inventory slots
Replaces the contents of a container window. Sent by the server upon initialization of a container window or the player's inventory, and in response to state ID mismatches (see #Click Container).
Packet ID State Bound To Field Name Field Type Notes
0x13 Play Client Window ID Unsigned Byte The ID of window which items are being sent for. 0 for player inventory. The client ignores any packets targeting a Window ID other than the current one. However, an exception is made for the player inventory, which may be targeted at any time. (The Notchian server does not appear to utilize this special case.)
State ID VarInt A server-managed sequence number used to avoid desynchronization; see #Click Container.
Count VarInt Number of elements in the following array.
Slot Data Array of Slot
Carried Item Slot Item being dragged with the mouse.
See inventory windows for further information about how slots are indexed. Use Open Screen to open the container on the client.
Set Container Property
This packet is used to inform the client that part of a GUI window should be updated.
Packet ID State Bound To Field Name Field Type Notes
0x14 Play Client Window ID Unsigned Byte
Property Short The property to be updated, see below.
Value Short The new value for the property, see below.
The meaning of the Property field depends on the type of the window. The following table shows the known combinations of window type and property, and how the value is to be interpreted.
Window type Property Value
Furnace 0: Fire icon (fuel left) counting from fuel burn time down to 0 (in-game ticks)
1: Maximum fuel burn time fuel burn time or 0 (in-game ticks)
2: Progress arrow counting from 0 to maximum progress (in-game ticks)
3: Maximum progress always 200 on the notchian server
Enchantment Table 0: Level requirement for top enchantment slot The enchantment's xp level requirement
1: Level requirement for middle enchantment slot
2: Level requirement for bottom enchantment slot
3: The enchantment seed Used for drawing the enchantment names (in SGA) clientside. The same seed is used to calculate enchantments, but some of the data isn't sent to the client to prevent easily guessing the entire list (the seed value here is the regular seed bitwise and 0xFFFFFFF0 ).
4: Enchantment ID shown on mouse hover over top enchantment slot The enchantment id (set to -1 to hide it), see below for values
5: Enchantment ID shown on mouse hover over middle enchantment slot
6: Enchantment ID shown on mouse hover over bottom enchantment slot
7: Enchantment level shown on mouse hover over the top slot The enchantment level (1 = I, 2 = II, 6 = VI, etc.), or -1 if no enchant
8: Enchantment level shown on mouse hover over the middle slot
9: Enchantment level shown on mouse hover over the bottom slot
Beacon 0: Power level 0-4, controls what effect buttons are enabled
1: First potion effect Potion effect ID for the first effect, or -1 if no effect
2: Second potion effect Potion effect ID for the second effect, or -1 if no effect
Anvil 0: Repair cost The repair's cost in xp levels
Brewing Stand 0: Brew time 0 – 400, with 400 making the arrow empty, and 0 making the arrow full
1: Fuel time 0 - 20, with 0 making the arrow empty, and 20 making the arrow full
Stonecutter 0: Selected recipe The index of the selected recipe. -1 means none is selected.
Loom 0: Selected pattern The index of the selected pattern. 0 means none is selected, 0 is also the internal id of the "base" pattern.
Lectern 0: Page number The current page number, starting from 0.
For an enchanting table, the following numerical IDs are used:
Numerical ID Enchantment ID Enchantment Name
0 minecraft:protection Protection
1 minecraft:fire_protection Fire Protection
2 minecraft:feather_falling Feather Falling
3 minecraft:blast_protection Blast Protection
4 minecraft:projectile_protection Projectile Protection
5 minecraft:respiration Respiration
6 minecraft:aqua_affinity Aqua Affinity
7 minecraft:thorns Thorns
8 minecraft:depth_strider Depth Strider
9 minecraft:frost_walker Frost Walker
10 minecraft:binding_curse Curse of Binding
11 minecraft:soul_speed Soul Speed
12 minecraft:swift_sneak Swift Sneak
13 minecraft:sharpness Sharpness
14 minecraft:smite Smite
15 minecraft:bane_of_arthropods Bane of Arthropods
16 minecraft:knockback Knockback
17 minecraft:fire_aspect Fire Aspect
18 minecraft:looting Looting
19 minecraft:sweeping_edge Sweeping Edge
20 minecraft:efficiency Efficiency
21 minecraft:silk_touch Silk Touch
22 minecraft:unbreaking Unbreaking
23 minecraft:fortune Fortune
24 minecraft:power Power
25 minecraft:punch Punch
26 minecraft:flame Flame
27 minecraft:infinity Infinity
28 minecraft:luck_of_the_sea Luck of the Sea
29 minecraft:lure Lure
30 minecraft:loyalty Loyalty
31 minecraft:impaling Impaling
32 minecraft:riptide Riptide
33 minecraft:channeling Channeling
34 minecraft:multishot Multishot
35 minecraft:quick_charge Quick Charge
36 minecraft:piercing Piercing
37 minecraft:density Density
38 minecraft:breach Breach
39 minecraft:wind_burst Wind Burst
40 minecraft:mending Mending
41 minecraft:vanishing_curse Curse of Vanishing
Set Container Slot
Sent by the server when an item in a slot (in a window) is added/removed.
Packet ID State Bound To Field Name Field Type Notes
0x15 Play Client Window ID Byte The window which is being updated. 0 for player inventory. The client ignores any packets targeting a Window ID other than the current one; see below for exceptions.
State ID VarInt A server-managed sequence number used to avoid desynchronization; see #Click Container.
Slot Short The slot that should be updated.
Slot Data Slot
If Window ID is 0, the hotbar and offhand slots (slots 36 through 45) may be updated even when a different container window is open. (The Notchian server does not appear to utilize this special case.) Updates are also restricted to those slots when the player is looking at a creative inventory tab other than the survival inventory. (The Notchian server does not handle this restriction in any way, leading to MC-242392.)
If Window ID is -1, the item being dragged with the mouse is set. In this case, State ID and Slot are ignored.
If Window ID is -2, any slot in the player's inventory can be updated irrespective of the current container window. In this case, State ID is ignored, and the Notchian server uses a bogus value of 0. Used by the Notchian server to implement the #Pick Item functionality.
When a container window is open, the server never sends updates targeting Window ID 0—all of the window types include slots for the player inventory. The client must automatically apply changes targeting the inventory portion of a container window to the main inventory; the server does not resend them for ID 0 when the window is closed. However, since the armor and offhand slots are only present on ID 0, updates to those slots occurring while a window is open must be deferred by the server until the window's closure.
Cookie Request (play)
Requests a cookie that was previously stored.
Packet ID State Bound To Field Name Field Type Notes
0x16 Play Client Key Identifier The identifier of the cookie.
Set Cooldown
Applies a cooldown period to all items with the given type. Used by the Notchian server with enderpearls. This packet should be sent when the cooldown starts and also when the cooldown ends (to compensate for lag), although the client will end the cooldown automatically. Can be applied to any item, note that interactions still get sent to the server with the item but the client does not play the animation nor attempt to predict results (i.e block placing).
Packet ID State Bound To Field Name Field Type Notes
0x17 Play Client Item ID VarInt Numeric ID of the item to apply a cooldown to.
Cooldown Ticks VarInt Number of ticks to apply a cooldown for, or 0 to clear the cooldown.
Chat Suggestions
Unused by the Notchian server. Likely provided for custom servers to send chat message completions to clients.
Packet ID State Bound To Field Name Field Type Notes
0x18 Play Client Action VarInt Enum 0: Add, 1: Remove, 2: Set
Count VarInt Number of elements in the following array.
Entries Array of String (32767)
Clientbound Plugin Message (play)
Main article: Plugin channels
Mods and plugins can use this to send their data. Minecraft itself uses several plugin channels. These internal channels are in the minecraft namespace.
More information on how it works on Dinnerbone's blog. More documentation about internal and popular registered channels are here.
Packet ID State Bound To Field Name Field Type Notes
0x19 Play Client Channel Identifier Name of the plugin channel used to send the data.
Data Byte Array (1048576) Any data. The length of this array must be inferred from the packet length.
In Notchian client, the maximum data length is 1048576 bytes.
Damage Event

and damage was dealt indirectly, such as by the use of a projectile, this field will contain the ID of such projectile;
and damage was dealt dirctly, such as by manually attacking, this field will contain the same value as Source Cause ID.

The Notchian server sends the Source Position when the damage was dealt by the /damage command and a position was specified
Debug Sample
Sample data that is sent periodically after the client has subscribed with Debug Sample Subscription.
The Notchian server only sends debug samples to players that are server operators.
Packet ID State Bound To Field Name Field Type Notes
0x1B Play Client Sample Length VarInt The length of the following array.
Sample Long Array Array of type-dependent samples.
Sample Type VarInt Enum See below.
Id Name Description
0 Tick time Four different tick-related metrics, each one represented by one long on the array.
They are measured in nano-seconds, and are as follows:

Full tick time: Aggregate of the three times below;
Server tick time: Main server tick logic;
Tasks time: Tasks scheduled to execute after the main logic;
Idle time: Time idling to complete the full 50ms tick cycle.

Delete Message
Removes a message from the client's chat. This only works for messages with signatures, system messages cannot be deleted with this packet.
Packet ID State Bound To Field Name Field Type Notes
0x1C Play Client Message ID VarInt The message Id + 1, used for validating message signature. The next field is present only when value of this field is equal to 0.
Signature Optional Byte Array (256) The previous message's signature. Always 256 bytes and not length-prefixed.
Disconnect (play)
Sent by the server before it disconnects a client. The client assumes that the server has already closed the connection by the time the packet arrives.
Packet ID State Bound To Field Name Field Type Notes
0x1D Play Client Reason Text Component Displayed to the client when the connection terminates.
Disguised Chat Message
Main article: Chat
Sends the client a chat message, but without any message signing information.
The Notchian server uses this packet when the console is communicating with players through commands, such as /say , /tell , /me , among others.
Packet ID State Bound To Field Name Field Type Notes
0x1E Play Client Message Text Component This is used as the content parameter when formatting the message on the client.
Chat Type VarInt The type of chat in the minecraft:chat_type registry, defined by the Registry Data packet.
Sender Name Text Component The name of the one sending the message, usually the sender's display name.
This is used as the sender parameter when formatting the message on the client.
This is used as the target parameter when formatting the message on the client.
Entity Event
Entity statuses generally trigger an animation for an entity. The available statuses vary by the entity's type (and are available to subclasses of that type as well).
Packet ID State Bound To Field Name Field Type Notes
0x1F Play Client Entity ID Int
Entity Status Byte Enum See Entity statuses for a list of which statuses are valid for each type of entity.
Explosion
Sent when an explosion occurs (creepers, TNT, and ghast fireballs).
Each block in Records is set to air. Coordinates for each axis in record is int(X) + record.x
Packet ID State Bound To Field Name Field Type Notes
0x20 Play Client X Double
Y Double
Z Double
Strength Float If the strength is greater or equal to 2.0, or the block interaction is not 0 (keep), large explosion particles are used. Otherwise, small explosion particles are used.
Record Count VarInt Number of elements in the following array.
Records Array of (Byte, Byte, Byte) Each record is 3 signed bytes long; the 3 bytes are the XYZ (respectively) signed offsets of affected blocks.
Player Motion X Float X velocity of the player being pushed by the explosion.
Player Motion Y Float Y velocity of the player being pushed by the explosion.
Player Motion Z Float Z velocity of the player being pushed by the explosion.
Block Interaction VarInt Enum 0 = keep, 1 = destroy, 2 = destroy_with_decay, 3 = trigger_block.
Small Explosion Particle ID VarInt The particle ID listed in Particles.
Small Explosion Particle Data Varies Particle data as specified in Particles.
Large Explosion Particle ID VarInt The particle ID listed in Particles.
Large Explosion Particle Data Varies Particle data as specified in Particles.
Explosion Sound Sound Name Identifier The name of the sound played.
Has Fixed Range Optional Boolean Whether is has fixed range.
Range Optional Float The fixed range of the sound. Only present if previous boolean is true.
Unload Chunk
Tells the client to unload a chunk column.
Packet ID State Bound To Field Name Field Type Notes
0x21 Play Client Chunk Z Int Block coordinate divided by 16, rounded down.
Chunk X Int Block coordinate divided by 16, rounded down.
Note: The order is inverted, because the client reads this packet as one big-endian Long, with Z being the upper 32 bits.
It is legal to send this packet even if the given chunk is not currently loaded.
Game Event
Used for a wide variety of game events, from weather to bed use to game mode to demo messages.
Packet ID State Bound To Field Name Field Type Notes
0x22 Play Client Event Unsigned Byte See below.
Value Float Depends on Event.
Event Effect Value
0 No respawn block available Note: Displays message 'block.minecraft.spawn.not_valid' (You have no home bed or charged respawn anchor, or it was obstructed) to the player.
1 Begin raining
2 End raining
3 Change game mode 0: Survival, 1: Creative, 2: Adventure, 3: Spectator.
4 Win game 0: Just respawn player.
1: Roll the credits and respawn player.
Note that 1 is only sent by notchian server when player has not yet achieved advancement "The end?", else 0 is sent.
5 Demo event 0: Show welcome to demo screen.
101: Tell movement controls.
102: Tell jump control.
103: Tell inventory control.
104: Tell that the demo is over and print a message about how to take a screenshot.
6 Arrow hit player Note: Sent when any player is struck by an arrow.
7 Rain level change Note: Seems to change both sky color and lighting.
Rain level ranging from 0 to 1.
8 Thunder level change Note: Seems to change both sky color and lighting (same as Rain level change, but doesn't start rain). It also requires rain to render by notchian client.
Thunder level ranging from 0 to 1.
9 Play pufferfish sting sound
10 Play elder guardian mob appearance (effect and sound)
11 Enable respawn screen 0: Enable respawn screen.
1: Immediately respawn (sent when the doImmediateRespawn gamerule changes).
12 Limited crafting 0: Disable limited crafting.
1: Enable limited crafting (sent when the doLimitedCrafting gamerule changes).
13 Start waiting for level chunks Instructs the client to begin the waiting process for the level chunks.
Sent by the server after the level is cleared on the client and is being re-sent (either during the first, or subsequent reconfigurations).
Open Horse Screen
This packet is used exclusively for opening the horse GUI. Open Screen is used for all other GUIs. The client will not open the inventory if the Entity ID does not point to an horse-like animal.
Packet ID State Bound To Field Name Field Type Notes
0x23 Play Client Window ID Unsigned Byte
Slot count VarInt
Entity ID Int
Hurt Animation
Plays a bobbing animation for the entity receiving damage.
Packet ID State Bound To Field Name Field Type Notes
0x24 Play Client
Entity ID VarInt The ID of the entity taking damage
Yaw Float The direction the damage is coming from in relation to the entity
Initialize World Border
Packet ID State Bound To Field Name Field Type Notes
0x25 Play Client X Double
Z Double
Old Diameter Double Current length of a single side of the world border, in meters.
New Diameter Double Target length of a single side of the world border, in meters.
Speed VarLong Number of real-time milliseconds until New Diameter is reached. It appears that Notchian server does not sync world border speed to game ticks, so it gets out of sync with server lag. If the world border is not moving, this is set to 0.
Portal Teleport Boundary VarInt Resulting coordinates from a portal teleport are limited to ±value. Usually 29999984.
Warning Blocks VarInt In meters.
Warning Time VarInt In seconds as set by /worldborder warning time .
The Notchian client determines how solid to display the warning by comparing to whichever is higher, the warning distance or whichever is lower, the distance from the current diameter to the target diameter or the place the border will be after warningTime seconds. In pseudocode:
distance = max(min(resizeSpeed * 1000 * warningTime, abs(targetDiameter - currentDiameter)), warningDistance); if (playerDistance distance) warning = 1.0 - playerDistance / distance; > else warning = 0.0; >
Clientbound Keep Alive (play)
The server will frequently send out a keep-alive, each containing a random ID. The client must respond with the same payload (see Serverbound Keep Alive). If the client does not respond to a Keep Alive packet within 15 seconds after it was sent, the server kicks the client. Vice versa, if the server does not send any keep-alives for 20 seconds, the client will disconnect and yields a "Timed out" exception.
The Notchian server uses a system-dependent time in milliseconds to generate the keep alive ID value.
Packet ID State Bound To Field Name Field Type Notes
0x26 Play Client Keep Alive ID Long
Chunk Data and Update Light
Main article: Chunk Format See also: #Unload Chunk
Sent when a chunk comes into the client's view distance, specifying its terrain, lighting and block entities.
The chunk must be within the view area previously specified with Set Center Chunk; see that packet for details.
It is not strictly necessary to send all block entities in this packet; it is still legal to send them with Block Entity Data later.
Packet ID State Bound To Field Name Field Type Notes
0x27 Play Client Chunk X Int Chunk coordinate (block coordinate divided by 16, rounded down)
Chunk Z Int Chunk coordinate (block coordinate divided by 16, rounded down)
Heightmaps NBT See Chunk Format#Heightmaps structure
Size VarInt Size of Data in bytes
Data Byte Array See Chunk Format#Data structure
Number of block entities VarInt Number of elements in the following array
Block Entity Packed XZ Array Unsigned Byte The packed section coordinates are relative to the chunk they are in. Values 0-15 are valid.
packed_xz = ((blockX & 15) > 4, z = packed_xz & 15 // decode
Unlike the Update Light packet which uses the same format, setting the bit corresponding to a section to 0 in both of the block light or sky light masks does not appear to be useful, and the results in testing have been highly inconsistent.
World Event
The following information needs to be added to this page:
The events listed below are not up-to-date with the latest release version, being either improperly documented or missing from the list altogether.
Sent when a client is to play a sound or particle effect.
By default, the Minecraft client adjusts the volume of sound effects based on distance. The final boolean field is used to disable this, and instead the effect is played from 2 blocks away in the correct direction. Currently this is only used for effect 1023 (wither spawn), effect 1028 (enderdragon death), and effect 1038 (end portal opening); it is ignored on other effects.
Packet ID State Bound To Field Name Field Type Notes
0x28 Play Client Event Int The event, see below.
Location Position The location of the event.
Data Int Extra data for certain events, see below.
Disable Relative Volume Boolean See above.
ID Name Data
Sound
1000 Dispenser dispenses
1001 Dispenser fails to dispense
1002 Dispenser shoots
1003 Ender eye launched
1004 Firework shot
1009 Fire extinguished
1010 Play record An ID in the minecraft:item registry, corresponding to a record item . If the ID doesn't correspond to a record, the packet is ignored. Any record already being played at the given location is overwritten. See Data Generators for information on item IDs.
1011 Stop record
1015 Ghast warns
1016 Ghast shoots
1017 Enderdragon shoots
1018 Blaze shoots
1019 Zombie attacks wood door
1020 Zombie attacks iron door
1021 Zombie breaks wood door
1022 Wither breaks block
1023 Wither spawned
1024 Wither shoots
1025 Bat takes off
1026 Zombie infects
1027 Zombie villager converted
1028 Ender dragon death
1029 Anvil destroyed
1030 Anvil used
1031 Anvil landed
1032 Portal travel
1033 Chorus flower grown
1034 Chorus flower died
1035 Brewing stand brewed
1038 End portal created in overworld
1039 Phantom bites
1040 Zombie converts to drowned
1041 Husk converts to zombie by drowning
1042 Grindstone used
1043 Book page turned
1044 Smithing table used
1045 Pointed dripstone landing
1046 Lava dripping on cauldron from dripstone
1047 Water dripping on cauldron from dripstone
1048 Skeleton converts to stray
1049 Crafter successfully crafts item
1050 Crafter fails to craft item
Particle
1500 Composter composts
1501 Lava converts block (either water to stone, or removes existing blocks such as torches)
1502 Redstone torch burns out
1503 Ender eye placed
1504 Fluid drips from dripstone
1505 Bonemeal particles How many particles to spawn.
2000 Spawns 10 smoke particles, e.g. from a fire Direction, see below.
2001 Block break + block break sound Block state ID (see Chunk Format#Block state registry).
2002 Splash potion. Particle effect + glass break sound. RGB color as an integer (e.g. 8364543 for #7FA1FF).
2003 Eye of Ender entity break animation — particles and sound
2004 Mob spawn particle effect: smoke + flames
2006 Dragon breath
2007 Instant splash potion. Particle effect + glass break sound. RGB color as an integer (e.g. 8364543 for #7FA1FF).
2008 Ender dragon destroys block
2009 Wet sponge vaporizes in nether
3000 End gateway spawn
3001 Enderdragon growl
3002 Electric spark
3003 Copper apply wax
3004 Copper remove wax
3005 Copper scrape oxidation
ID Direction
0 Down
1 Up
2 North
3 South
4 West
5 East
Particle
Displays the named particle
Packet ID State Bound To Field Name Field Type Notes
0x29 Play Client Long Distance Boolean If true, particle distance increases from 256 to 65536.
X Double X position of the particle.
Y Double Y position of the particle.
Z Double Z position of the particle.
Offset X Float This is added to the X position after being multiplied by random.nextGaussian() .
Offset Y Float This is added to the Y position after being multiplied by random.nextGaussian() .
Offset Z Float This is added to the Z position after being multiplied by random.nextGaussian() .
Max Speed Float
Particle Count Int The number of particles to create.
Particle ID VarInt The particle ID listed in Particles.
Data Varies Particle data as specified in Particles.
Update Light
Updates light levels for a chunk. See Light for information on how lighting works in Minecraft.
Packet ID State Bound To Field Name Field Type Notes
0x2A Play Client Chunk X VarInt Chunk coordinate (block coordinate divided by 16, rounded down)
Chunk Z VarInt Chunk coordinate (block coordinate divided by 16, rounded down)
Sky Light Mask BitSet BitSet containing bits for each section in the world + 2. Each set bit indicates that the corresponding 16×16×16 chunk section has data in the Sky Light array below. The least significant bit is for blocks 16 blocks to 1 block below the min world height (one section below the world), while the most significant bit covers blocks 1 to 16 blocks above the max world height (one section above the world).
Block Light Mask BitSet BitSet containing bits for each section in the world + 2. Each set bit indicates that the corresponding 16×16×16 chunk section has data in the Block Light array below. The order of bits is the same as in Sky Light Mask.
Empty Sky Light Mask BitSet BitSet containing bits for each section in the world + 2. Each set bit indicates that the corresponding 16×16×16 chunk section has all zeros for its Sky Light data. The order of bits is the same as in Sky Light Mask.
Empty Block Light Mask BitSet BitSet containing bits for each section in the world + 2. Each set bit indicates that the corresponding 16×16×16 chunk section has all zeros for its Block Light data. The order of bits is the same as in Sky Light Mask.
Sky Light array count VarInt Number of entries in the following array; should match the number of bits set in Sky Light Mask
Sky Light arrays Length Array VarInt Length of the following array in bytes (always 2048)
Sky Light array Byte Array (2048) There is 1 array for each bit set to true in the sky light mask, starting with the lowest value. Half a byte per light value.
Block Light array count VarInt Number of entries in the following array; should match the number of bits set in Block Light Mask
Block Light arrays Length Array VarInt Length of the following array in bytes (always 2048)
Block Light array Byte Array (2048) There is 1 array for each bit set to true in the block light mask, starting with the lowest value. Half a byte per light value.
A bit will never be set in both the block light mask and the empty block light mask, though it may be present in neither of them (if the block light does not need to be updated for the corresponding chunk section). The same applies to the sky light mask and the empty sky light mask.
Login (play)
The following information needs to be added to this page:
Although the number of portal cooldown ticks is included in this packet, the whole portal usage process is still dictated entirely by the server. What kind of effect does this value have on the client, if any?
See Protocol Encryption for information on logging in.
Packet ID State Bound To Field Name Field Type Notes
0x2B Play Client Entity ID Int The player's Entity ID (EID).
Is hardcore Boolean
Dimension Count VarInt Size of the following array.
Dimension Names Array of Identifier Identifiers for all dimensions on the server.
Max Players VarInt Was once used by the client to draw the player list, but now is ignored.
View Distance VarInt Render distance (2-32).
Simulation Distance VarInt The distance that the client will process specific things, such as entities.
Reduced Debug Info Boolean If true, a Notchian client shows reduced information on the debug screen . For servers in development, this should almost always be false.
Enable respawn screen Boolean Set to false when the doImmediateRespawn gamerule is true.
Do limited crafting Boolean Whether players can only craft recipes they have already unlocked. Currently unused by the client.
Dimension Type VarInt The ID of the type of dimension in the minecraft:dimension_type registry, defined by the Registry Data packet.
Dimension Name Identifier Name of the dimension being spawned into.
Hashed seed Long First 8 bytes of the SHA-256 hash of the world's seed. Used client side for biome noise
Game mode Unsigned Byte 0: Survival, 1: Creative, 2: Adventure, 3: Spectator.
Previous Game mode Byte -1: Undefined (null), 0: Survival, 1: Creative, 2: Adventure, 3: Spectator. The previous game mode. Vanilla client uses this for the debug (F3 + N & F3 + F4) game mode switch. (More information needed)
Is Debug Boolean True if the world is a debug mode world; debug mode worlds cannot be modified and have predefined blocks.
Is Flat Boolean True if the world is a superflat world; flat worlds have different void fog and a horizon at y=0 instead of y=63.
Has death location Boolean If true, then the next two fields are present.
Death dimension name Optional Identifier Name of the dimension the player died in.
Death location Optional Position The location that the player died at.
Portal cooldown VarInt The number of ticks until the player can use the portal again.
Enforces Secure Chat Boolean
Map Data
Updates a rectangular area on a map item.
Packet ID State Bound To Field Name Field Type Notes
0x2C Play Client Map ID VarInt Map ID of the map being modified
Scale Byte From 0 for a fully zoomed-in map (1 block per pixel) to 4 for a fully zoomed-out map (16 blocks per pixel)
Locked Boolean True if the map has been locked in a cartography table
Has Icons Boolean
Icon Count Optional VarInt Number of elements in the following array. Only present if previous Boolean is true.
Icon Type Optional Array VarInt Enum See below
X Byte Map coordinates: -128 for furthest left, +127 for furthest right
Z Byte Map coordinates: -128 for highest, +127 for lowest
Direction Byte 0-15
Has Display Name Boolean
Display Name Optional Text Component Only present if previous Boolean is true
Color Patch Columns Unsigned Byte Number of columns updated
Rows Optional Unsigned Byte Only if Columns is more than 0; number of rows updated
X Optional Unsigned Byte Only if Columns is more than 0; x offset of the westernmost column
Z Optional Unsigned Byte Only if Columns is more than 0; z offset of the northernmost row
Length Optional VarInt Only if Columns is more than 0; length of the following array
Data Optional Array of Unsigned Byte Only if Columns is more than 0; see Map item format
For icons, a direction of 0 is a vertical icon and increments by 22.5° (360/16).
Types are based off of rows and columns in map_icons.png :
Icon type Result
0 White arrow (players)
1 Green arrow (item frames)
2 Red arrow
3 Blue arrow
4 White cross
5 Red pointer
6 White circle (off-map players)
7 Small white circle (far-off-map players)
8 Mansion
9 Monument
10 White Banner
11 Orange Banner
12 Magenta Banner
13 Light Blue Banner
14 Yellow Banner
15 Lime Banner
16 Pink Banner
17 Gray Banner
18 Light Gray Banner
19 Cyan Banner
20 Purple Banner
21 Blue Banner
22 Brown Banner
23 Green Banner
24 Red Banner
25 Black Banner
26 Treasure marker
Merchant Offers
The list of trades a villager NPC is offering.
Packet ID State Bound To Field Name Field Type Notes
0x2D Play Client Window ID VarInt The ID of the window that is open; this is an int rather than a byte.
Size VarInt The number of trades in the following array.
Trades Input item 1 Array Trade Item See below. The first item the player has to supply for this villager trade. The count of the item stack is the default "price" of this trade.
Output item Slot The item the player will receive from this villager trade.
Input item 2 Optional Trade Item The second item the player has to supply for this villager trade. May be an empty slot.
Trade disabled Boolean True if the trade is disabled; false if the trade is enabled.
Number of trade uses Int Number of times the trade has been used so far. If equal to the maximum number of trades, the client will display a red X.
Maximum number of trade uses Int Number of times this trade can be used before it's exhausted.
XP Int Amount of XP the villager will earn each time the trade is used.
Special Price Int Can be zero or negative. The number is added to the price when an item is discounted due to player reputation or other effects.
Price Multiplier Float Can be low (0.05) or high (0.2). Determines how much demand, player reputation, and temporary effects will adjust the price.
Demand Int If positive, causes the price to increase. Negative values seem to be treated the same as zero.
Villager level VarInt Appears on the trade GUI; meaning comes from the translation key merchant.level. + level.
1: Novice, 2: Apprentice, 3: Journeyman, 4: Expert, 5: Master.
Field Name Field Type Meaning
Item ID VarInt The item ID . Item IDs are distinct from block IDs; see Data Generators for more information.
Item Count VarInt The item count.
Size VarInt The number of components in the following array.
Components Component type Array VarInt Enum The type of component. See Structured components for more detail.
Component data Varies The component-dependent data. See Structured components for more detail.

Modifiers can increase or decrease the number of items for the first input slot. The second input slot and the output slot never change the number of items. The number of items may never be less than 1, and never more than the stack size. If special price and demand are both zero, only the default price is displayed. If either is non-zero, then the adjusted price is displayed next to the crossed-out default price. The adjusted prices is calculated as follows:
Adjusted price = default price + floor(default price x multiplier x demand) + special price

The merchant UI, for reference
Update Entity Position
This packet is sent by the server when an entity moves a small distance. The change in position is represented as a fixed-point number with 12 fraction bits and 4 integer bits. As such, the maximum movement distance along each axis is 8 blocks in the negative direction, or 7.999755859375 blocks in the positive direction. If the movement exceeds these limits, Teleport Entity should be sent instead.
Packet ID State Bound To Field Name Field Type Notes
0x2E Play Client Entity ID VarInt
Delta X Short Change in X position as currentX * 4096 - prevX * 4096 .
Delta Y Short Change in Y position as currentY * 4096 - prevY * 4096 .
Delta Z Short Change in Z position as currentZ * 4096 - prevZ * 4096 .
On Ground Boolean
Update Entity Position and Rotation
This packet is sent by the server when an entity rotates and moves. See #Update Entity Position for how the position is encoded.
Packet ID State Bound To Field Name Field Type Notes
0x2F Play Client Entity ID VarInt
Delta X Short Change in X position as currentX * 4096 - prevX * 4096 .
Delta Y Short Change in Y position as currentY * 4096 - prevY * 4096 .
Delta Z Short Change in Z position as currentZ * 4096 - prevZ * 4096 .
Yaw Angle New angle, not a delta.
Pitch Angle New angle, not a delta.
On Ground Boolean
Update Entity Rotation
This packet is sent by the server when an entity rotates.
Packet ID State Bound To Field Name Field Type Notes
0x30 Play Client Entity ID VarInt
Yaw Angle New angle, not a delta.
Pitch Angle New angle, not a delta.
On Ground Boolean
Move Vehicle
Note that all fields use absolute positioning and do not allow for relative positioning.
Packet ID State Bound To Field Name Field Type Notes
0x31 Play Client X Double Absolute position (X coordinate).
Y Double Absolute position (Y coordinate).
Z Double Absolute position (Z coordinate).
Yaw Float Absolute rotation on the vertical axis, in degrees.
Pitch Float Absolute rotation on the horizontal axis, in degrees.
Open Book
Sent when a player right clicks with a signed book. This tells the client to open the book GUI.
Packet ID State Bound To Field Name Field Type Notes
0x32 Play Client Hand VarInt Enum 0: Main hand, 1: Off hand .
Open Screen
This is sent to the client when it should open an inventory, such as a chest, workbench, furnace, or other container. Resending this packet with already existing window id, will update the window title and window type without closing the window.
This message is not sent to clients opening their own inventory, nor do clients inform the server in any way when doing so. From the server's perspective, the inventory is always "open" whenever no other windows are.
Packet ID State Bound To Field Name Field Type Notes
0x33 Play Client Window ID VarInt An identifier for the window to be displayed. Notchian server implementation is a counter, starting at 1. There can only be one window at a time; this is only used to ignore outdated packets targeting already-closed windows. Note also that the Window ID field in most other packets is only a single byte, and indeed, the Notchian server wraps around after 100.
Window Type VarInt The window type to use for display. Contained in the minecraft:menu registry; see Inventory for the different values.
Window Title Text Component The title of the window.
Open Sign Editor
Sent when the client has placed a sign and is allowed to send Update Sign. There must already be a sign at the given location (which the client does not do automatically) - send a Block Update first.
Packet ID State Bound To Field Name Field Type Notes
0x34 Play Client Location Position
Is Front Text Boolean Whether the opened editor is for the front or on the back of the sign
Ping (play)
Packet is not used by the Notchian server. When sent to the client, client responds with a Pong packet with the same id.
Packet ID State Bound To Field Name Field Type Notes
0x35 Play Client ID Int
Ping Response (play)
Packet ID State Bound To Field Name Field Type Notes
0x36 Play Client Payload Long Should be the same as sent by the client.
Place Ghost Recipe
Response to the serverbound packet (Place Recipe), with the same recipe ID. Appears to be used to notify the UI.
Packet ID State Bound To Field Name Field Type Notes
0x37 Play Client Window ID Byte
Recipe Identifier A recipe ID.
Player Abilities (clientbound)
The latter 2 floats are used to indicate the flying speed and field of view respectively, while the first byte is used to determine the value of 4 booleans.
Packet ID State Bound To Field Name Field Type Notes
0x38 Play Client Flags Byte Bit field, see below.
Flying Speed Float 0.05 by default.
Field of View Modifier Float Modifies the field of view, like a speed potion. A Notchian server will use the same value as the movement speed sent in the Update Attributes packet, which defaults to 0.1 for players.
About the flags:
Field Bit
Invulnerable 0x01
Flying 0x02
Allow Flying 0x04
Creative Mode (Instant Break) 0x08
Player Chat Message
Main article: Chat
Sends the client a chat message from a player.
Currently a lot is unknown about this packet, blank descriptions are for those that are unknown
Packet ID State Bound To Sector Field Name Field Type Notes
0x39 Play Client Header Sender UUID Used by the Notchian client for the disableChat launch option. Setting both longs to 0 will always display the message regardless of the setting.
Index VarInt
Message Signature Present Boolean States if a message signature is present
Message Signature bytes Optional Byte Array (256) Only present if Message Signature Present is true. Cryptography, the signature consists of the Sender UUID, Session UUID from the Player Session packet, Index, Salt, Timestamp in epoch seconds, the length of the original chat content, the original content itself, the length of Previous Messages, and all of the Previous message signatures. These values are hashed with SHA-256 and signed using the RSA cryptosystem. Modifying any of these values in the packet will cause this signature to fail. This buffer is always 256 bytes long and it is not length-prefixed.
Body Message String (256) Raw (optionally) signed sent message content.
This is used as the content parameter when formatting the message on the client.
This is used as the sender parameter when formatting the message on the client.
This is used as the target parameter when formatting the message on the client.

Player Chat Handling Logic
The filter type mask should NOT be specified unless partially filtered is selected
ID Name Description
0 PASS_THROUGH Message is not filtered at all
1 FULLY_FILTERED Message is fully filtered
2 PARTIALLY_FILTERED Only some characters in the message are filtered
End Combat
Unused by the Notchian client. This data was once used for twitch.tv metadata circa 1.8.
Packet ID State Bound To Field Name Field Type Notes
0x3A Play Client Duration VarInt Length of the combat in ticks.
Enter Combat
Unused by the Notchian client. This data was once used for twitch.tv metadata circa 1.8.
Packet ID State Bound To Field Name Field Type Notes
0x3B Play Client no fields
Combat Death
Used to send a respawn screen.
Packet ID State Bound To Field Name Field Type Notes
0x3C Play Client Player ID VarInt Entity ID of the player that died (should match the client's entity ID).
Message Text Component The death message.
Player Info Remove
Used by the server to remove players from the player list.
Packet ID State Bound To Field Name Field Type Notes
0x3D Play Client Number of Players VarInt Number of elements in the following array.
Player Player Id Array of UUID UUIDs of players to remove.
Player Info Update
Sent by the server to update the user list ( in the client).
Packet ID State Bound To Field Name Field Type Notes
0x3E Play Client Actions Byte Determines what actions are present.
Number Of Players VarInt Number of elements in the following array.
Players UUID Array UUID The player UUID
Player Actions Array of Player Actions The length of this array is determined by the number of Player Actions that give a non-zero value when applying its mask to the actions flag. For example given the decimal number 5, binary 00000101. The masks 0x01 and 0x04 would return a non-zero value, meaning the Player Actions array would include two actions: Add Player and Update Game Mode.
Player Actions Action Mask Field Name Type Notes
Add Player 0x01 Name String (16)
Number Of Properties VarInt Number of elements in the following array.
Property Name Array String (32767)
Value String (32767)
Is Signed Boolean
Signature Optional String (32767) Only if Is Signed is true.
Initialize Chat 0x02 Has Signature Data Boolean
Chat session ID UUID Only sent if Has Signature Data is true.
Public key expiry time Long Key expiry time, as a UNIX timestamp in milliseconds. Only sent if Has Signature Data is true.
Encoded public key size VarInt Size of the following array. Only sent if Has Signature Data is true. Maximum length is 512 bytes.
Encoded public key Byte Array (512) The player's public key, in bytes. Only sent if Has Signature Data is true.
Public key signature size VarInt Size of the following array. Only sent if Has Signature Data is true. Maximum length is 4096 bytes.
Public key signature Byte Array (4096) The public key's digital signature. Only sent if Has Signature Data is true.
Update Game Mode 0x04 Game Mode VarInt
Update Listed 0x08 Listed Boolean Whether the player should be listed on the player list.
Update Latency 0x10 Ping VarInt Measured in milliseconds.
Update Display Name 0x20 Has Display Name Boolean
Display Name Optional Text Component Only sent if Has Display Name is true.
The properties included in this packet are the same as in Login Success, for the current player.
Ping values correspond with icons in the following way:

A ping that negative (i.e. not known to the server yet) will result in the no connection icon.
A ping under 150 milliseconds will result in 5 bars
A ping under 300 milliseconds will result in 4 bars
A ping under 600 milliseconds will result in 3 bars
A ping under 1000 milliseconds (1 second) will result in 2 bars
A ping greater than or equal to 1 second will result in 1 bar.

Look At
Used to rotate the client player to face the given location or entity (for /teleport [] facing ).
Packet ID State Bound To Field Name Field Type Notes
0x3F Play Client
Feet/eyes VarInt Enum Values are feet=0, eyes=1. If set to eyes, aims using the head position; otherwise aims using the feet position.
Target x Double x coordinate of the point to face towards.
Target y Double y coordinate of the point to face towards.
Target z Double z coordinate of the point to face towards.
Is entity Boolean If true, additional information about an entity is provided.
Entity ID Optional VarInt Only if is entity is true — the entity to face towards.
Entity feet/eyes Optional VarInt Enum Whether to look at the entity's eyes or feet. Same values and meanings as before, just for the entity's head/feet.
If the entity given by entity ID cannot be found, this packet should be treated as if is entity was false.
Synchronize Player Position
Teleports the client, e.g. during login, when using an ender pearl, in response to invalid move packets, etc.
Due to latency, the server may receive outdated movement packets sent before the client was aware of the teleport. To account for this, the server ignores all movement packets from the client until a Confirm Teleportation packet with an ID matching the one sent in the teleport packet is received.
Yaw is measured in degrees, and does not follow classical trigonometry rules. The unit circle of yaw on the XZ-plane starts at (0, 1) and turns counterclockwise, with 90 at (-1, 0), 180 at (0, -1) and 270 at (1, 0). Additionally, yaw is not clamped to between 0 and 360 degrees; any number is valid, including negative numbers and numbers greater than 360 (see MC-90097).
Pitch is measured in degrees, where 0 is looking straight ahead, -90 is looking straight up, and 90 is looking straight down.
Packet ID State Bound To Field Name Field Type Notes
0x40 Play Client X Double Absolute or relative position, depending on Flags.
Y Double Absolute or relative position, depending on Flags.
Z Double Absolute or relative position, depending on Flags.
Yaw Float Absolute or relative rotation on the X axis, in degrees.
Pitch Float Absolute or relative rotation on the Y axis, in degrees.
Flags Byte Reference the Flags table below. When the value of the this byte masked is zero the field is absolute, otherwise relative.
Teleport ID VarInt Client should confirm this packet with Confirm Teleportation containing the same Teleport ID.
Flags Field Hex Mask
X 0x01
Y 0x02
Z 0x04
Y_ROT (Pitch) 0x08
X_ROT (Yaw) 0x10
Update Recipe Book
Packet ID State Bound To Field Name Field Type Notes
0x41 Play Client
Action VarInt 0: init, 1: add, 2: remove.
Crafting Recipe Book Open Boolean If true, then the crafting recipe book will be open when the player opens its inventory.
Crafting Recipe Book Filter Active Boolean If true, then the filtering option is active when the players opens its inventory.
Smelting Recipe Book Open Boolean If true, then the smelting recipe book will be open when the player opens its inventory.
Smelting Recipe Book Filter Active Boolean If true, then the filtering option is active when the players opens its inventory.
Blast Furnace Recipe Book Open Boolean If true, then the blast furnace recipe book will be open when the player opens its inventory.
Blast Furnace Recipe Book Filter Active Boolean If true, then the filtering option is active when the players opens its inventory.
Smoker Recipe Book Open Boolean If true, then the smoker recipe book will be open when the player opens its inventory.
Smoker Recipe Book Filter Active Boolean If true, then the filtering option is active when the players opens its inventory.
Array size 1 VarInt Number of elements in the following array.
Recipe IDs Array of Identifier
Array size 2 Optional VarInt Number of elements in the following array, only present if action is 0 (init).
Recipe IDs Optional Array of Identifier Only present if mode is 0 (init)

0 (init) = All the recipes in list 1 will be tagged as displayed, and all the recipes in list 2 will be added to the recipe book. Recipes that aren't tagged will be shown in the notification.
1 (add) = All the recipes in the list are added to the recipe book and their icons will be shown in the notification.
2 (remove) = Remove all the recipes in the list. This allows them to be re-displayed when they are re-added.

Remove Entities
Sent by the server when an entity is to be destroyed on the client.
Packet ID State Bound To Field Name Field Type Notes
0x42 Play Client Count VarInt Number of elements in the following array.
Entity IDs Array of VarInt The list of entities to destroy.
Remove Entity Effect
Packet ID State Bound To Field Name Field Type Notes
0x43 Play Client Entity ID VarInt
Effect ID VarInt See this table .
Reset Score
This is sent to the client when it should remove a scoreboard item.
Packet ID State Bound To Field Name Field Type Notes
0x44 Play Client Entity Name String (32767) The entity whose score this is. For players, this is their username; for other entities, it is their UUID.
Has Objective Name Boolean Whether the score should be removed for the specified objective, or for all of them.
Objective Name Optional String (32767) The name of the objective the score belongs to. Only present if the previous field is true.
Remove Resource Pack (play)
Packet ID State Bound To Field Name Field Type Notes
0x45 Play Client Has UUID Boolean Whether a specific resource pack should be removed, or all of them.
UUID Optional UUID The UUID of the resource pack to be removed. Only present if the previous field is true.
Add Resource Pack (play)
Packet ID State Bound To Field Name Field Type Notes
0x46 Play Client UUID UUID The unique identifier of the resource pack.
URL String (32767) The URL to the resource pack.
Hash String (40) A 40 character hexadecimal, case-insensitive SHA-1 hash of the resource pack file.
If it's not a 40 character hexadecimal string, the client will not use it for hash verification and likely waste bandwidth.
Forced Boolean The Notchian client will be forced to use the resource pack from the server. If they decline they will be kicked from the server.
Has Prompt Message Boolean Whether a custom message should be used on the resource pack prompt.
Prompt Message Optional Text Component This is shown in the prompt making the client accept or decline the resource pack. Only present if the previous field is true.
Respawn
The following information needs to be added to this page:
Although the number of portal cooldown ticks is included in this packet, the whole portal usage process is still dictated entirely by the server. What kind of effect does this value have on the client, if any?
To change the player's dimension (overworld/nether/end), send them a respawn packet with the appropriate dimension, followed by prechunks/chunks for the new dimension, and finally a position and look packet. You do not need to unload chunks, the client will do it automatically.
Packet ID State Bound To Field Name Field Type Notes
0x47 Play Client Dimension Type VarInt The ID of type of dimension in the minecraft:dimension_type registry, defined by the Registry Data packet.
Dimension Name Identifier Name of the dimension being spawned into.
Hashed seed Long First 8 bytes of the SHA-256 hash of the world's seed. Used client side for biome noise
Game mode Unsigned Byte 0: Survival, 1: Creative, 2: Adventure, 3: Spectator.
Previous Game mode Byte -1: Undefined (null), 0: Survival, 1: Creative, 2: Adventure, 3: Spectator. The previous game mode. Vanilla client uses this for the debug (F3 + N & F3 + F4) game mode switch. (More information needed)
Is Debug Boolean True if the world is a debug mode world; debug mode worlds cannot be modified and have predefined blocks.
Is Flat Boolean True if the world is a superflat world; flat worlds have different void fog and a horizon at y=0 instead of y=63.
Has death location Boolean If true, then the next two fields are present.
Death dimension Name Optional Identifier Name of the dimension the player died in.
Death location Optional Position The location that the player died at.
Portal cooldown VarInt The number of ticks until the player can use the portal again.
Data kept Byte Bit mask. 0x01: Keep attributes, 0x02: Keep metadata. Tells which data should be kept on the client side once the player has respawned.
In the Notchian implementation, this is context dependent:

normal respawns (after death) keep no data;
exiting the end poem/credits keeps the attributes;
other dimension changes (portals or teleports) keep all data.

Avoid changing player's dimension to same dimension they were already in unless they are dead. If you change the dimension to one they are already in, weird bugs can occur, such as the player being unable to attack other players in new world (until they die and respawn).
Before 1.16, if you must respawn a player in the same dimension without killing them, send two respawn packets, one to a different world and then another to the world you want. You do not need to complete the first respawn; it only matters that you send two packets.
Set Head Rotation
Changes the direction an entity's head is facing.
While sending the Entity Look packet changes the vertical rotation of the head, sending this packet appears to be necessary to rotate the head horizontally.
Packet ID State Bound To Field Name Field Type Notes
0x48 Play Client Entity ID VarInt
Head Yaw Angle New angle, not a delta.
Update Section Blocks
Fired whenever 2 or more blocks are changed within the same chunk on the same tick.
Changing blocks in chunks not loaded by the client is unsafe (see note on Block Update).
Packet ID State Bound To Field Name Field Type Notes
0x49 Play Client Chunk section position Long Chunk section coordinate (encoded chunk x and z with each 22 bits, and section y with 20 bits, from left to right).
Blocks array size VarInt Number of elements in the following array.
Blocks Array of VarLong Each entry is composed of the block state id, shifted left by 12, and the relative block position in the chunk section (4 bits for x, z, and y, from left to right).
Chunk section position is encoded:
((sectionX & 0x3FFFFF) 42) | (sectionY & 0xFFFFF) | ((sectionZ & 0x3FFFFF) 20);
sectionX = long >> 42; sectionY = long 44 >> 44; sectionZ = long 22 >> 42;
Blocks are encoded:
blockStateId 12 | (blockLocalX 8 | blockLocalZ 4 | blockLocalY) //Uses the local position of the given block position relative to its respective chunk section
blockStateId = long >> 12; blockLocalX = (long >> 8) & 0xF; blockLocalY = long & 0xF; blockLocalZ = (long >> 4) & 0xF;
Select Advancements Tab
Sent by the server to indicate that the client should switch advancement tab. Sent either when the client switches tab in the GUI or when an advancement in another tab is made.
Packet ID State Bound To Field Name Field Type Notes
0x4A Play Client Has id Boolean Indicates if the next field is present.
Identifier Optional Identifier See below.
The Identifier can be one of the following:
Identifier
minecraft:story/root
minecraft:nether/root
minecraft:end/root
minecraft:adventure/root
minecraft:husbandry/root
If no or an invalid identifier is sent, the client will switch to the first tab in the GUI.
Server Data
Packet ID State Bound To Field Name Field Type Notes
0x4B Play Client MOTD Text Component
Has Icon Boolean
Size Optional VarInt Number of bytes in the following array. Only present if Has Icon is true.
Icon Optional Byte Array Icon bytes in the PNG format. Only present is Has Icon is true.
Set Action Bar Text
Displays a message above the hotbar. Equivalent to System Chat Message with Overlay set to true, except that chat message blocking isn't performed. Used by the Notchian server only to implement the /title command.
Packet ID State Bound To Field Name Field Type Notes
0x4C Play Client Action bar text Text Component
Set Border Center
Packet ID State Bound To Field Name Field Type Notes
0x4D Play Client X Double
Z Double
Set Border Lerp Size
Packet ID State Bound To Field Name Field Type Notes
0x4E Play Client Old Diameter Double Current length of a single side of the world border, in meters.
New Diameter Double Target length of a single side of the world border, in meters.
Speed VarLong Number of real-time milliseconds until New Diameter is reached. It appears that Notchian server does not sync world border speed to game ticks, so it gets out of sync with server lag. If the world border is not moving, this is set to 0.
Set Border Size
Packet ID State Bound To Field Name Field Type Notes
0x4F Play Client Diameter Double Length of a single side of the world border, in meters.
Set Border Warning Delay
Packet ID State Bound To Field Name Field Type Notes
0x50 Play Client Warning Time VarInt In seconds as set by /worldborder warning time .
Set Border Warning Distance
Packet ID State Bound To Field Name Field Type Notes
0x51 Play Client Warning Blocks VarInt In meters.
Set Camera
Sets the entity that the player renders from. This is normally used when the player left-clicks an entity while in spectator mode.
The player's camera will move with the entity and look where it is looking. The entity is often another player, but can be any type of entity. The player is unable to move this entity (move packets will act as if they are coming from the other entity).
If the given entity is not loaded by the player, this packet is ignored. To return control to the player, send this packet with their entity ID.
The Notchian server resets this (sends it back to the default entity) whenever the spectated entity is killed or the player sneaks, but only if they were spectating an entity. It also sends this packet whenever the player switches out of spectator mode (even if they weren't spectating an entity).
Packet ID State Bound To Field Name Field Type Notes
0x52 Play Client Camera ID VarInt ID of the entity to set the client's camera to.
The notchian client also loads certain shaders for given entities:

Creeper → shaders/post/creeper.json
Spider (and cave spider) → shaders/post/spider.json
Enderman → shaders/post/invert.json
Anything else → the current shader is unloaded

Set Held Item (clientbound)
Sent to change the player's slot selection.
Packet ID State Bound To Field Name Field Type Notes
0x53 Play Client Slot Byte The slot which the player has selected (0–8).
Set Center Chunk
Sets the center position of the client's chunk loading area. The area is square-shaped, spanning 2 × server view distance + 7 chunks on both axes (width, not radius!). Since the area's width is always an odd number, there is no ambiguity as to which chunk is the center.
The Notchian client ignores attempts to send chunks located outside the loading area, and immediately unloads any existing chunks no longer inside it.
The center chunk is normally the chunk the player is in, but apart from the implications on chunk loading, the (Notchian) client takes no issue with this not being the case. Indeed, as long as chunks are sent only within the default loading area centered on the world origin, it is not necessary to send this packet at all. This may be useful for servers with small bounded worlds, such as minigames, since it ensures chunks never need to be resent after the client has joined, saving on bandwidth.
The Notchian server sends this packet whenever the player moves across a chunk border horizontally, and also (according to testing) for any integer change in the vertical axis, even if it doesn't go across a chunk section border.
Packet ID State Bound To Field Name Field Type Notes
0x54 Play Client Chunk X VarInt Chunk X coordinate of the loading area center.
Chunk Z VarInt Chunk Z coordinate of the loading area center.
Set Render Distance
Sent by the integrated singleplayer server when changing render distance. This packet is sent by the server when the client reappears in the overworld after leaving the end.
Packet ID State Bound To Field Name Field Type Notes
0x55 Play Client View Distance VarInt Render distance (2-32).
Set Default Spawn Position
Sent by the server after login to specify the coordinates of the spawn point (the point at which players spawn at, and which the compass points to). It can be sent at any time to update the point compasses point at.
The client uses this as the default position of the player upon spawning, though it's a good idea to always override this default by sending Synchronize Player Position. When converting the position to floating point, 0.5 is added to the x and z coordinates and 1.0 to the y coordinate, so as to place the player centered on top of the specified block position.
Before receiving this packet, the client uses the default position 8, 64, 8, and angle 0.0 (resulting in a default player spawn position of 8.5, 65.0, 8.5).
Packet ID State Bound To Field Name Field Type Notes
0x56 Play Client Location Position Spawn location.
Angle Float The angle at which to respawn at.
Display Objective
This is sent to the client when it should display a scoreboard.
Packet ID State Bound To Field Name Field Type Notes
0x57 Play Client Position VarInt The position of the scoreboard. 0: list, 1: sidebar, 2: below name, 3 - 18: team specific sidebar, indexed as 3 + team color.
Score Name String (32767) The unique name for the scoreboard to be displayed.
Set Entity Metadata
Updates one or more metadata properties for an existing entity. Any properties not included in the Metadata field are left unchanged.
Packet ID State Bound To Field Name Field Type Notes
0x58 Play Client Entity ID VarInt
Metadata Entity Metadata
Link Entities
This packet is sent when an entity has been leashed to another entity.
Packet ID State Bound To Field Name Field Type Notes
0x59 Play Client Attached Entity ID Int Attached entity's EID.
Holding Entity ID Int ID of the entity holding the lead. Set to -1 to detach.
Set Entity Velocity
Velocity is in units of 1/8000 of a block per server tick (50ms); for example, -1343 would move (-1343 / 8000) = −0.167875 blocks per tick (or −3.3575 blocks per second).
Packet ID State Bound To Field Name Field Type Notes
0x5A Play Client Entity ID VarInt
Velocity X Short Velocity on the X axis.
Velocity Y Short Velocity on the Y axis.
Velocity Z Short Velocity on the Z axis.
Set Equipment
Packet ID State Bound To Field Name Field Type Notes
0x5B Play Client Entity ID VarInt Entity's ID.
Equipment Slot Array Byte Enum Equipment slot (see below). Also has the top bit set if another entry follows, and otherwise unset if this is the last item in the array.
Item Slot
Equipment slot can be one of the following:
ID Equipment slot
0 Main hand
1 Off hand
2 Boots
3 Leggings
4 Chestplate
5 Helmet
6 Body
Set Experience
Sent by the server when the client should change experience levels.
Packet ID State Bound To Field Name Field Type Notes
0x5C Play Client Experience bar Float Between 0 and 1.
Level VarInt
Total Experience VarInt See Experience#Leveling up on the Minecraft Wiki for Total Experience to Level conversion.
Set Health
Sent by the server to set the health of the player it is sent to.
Food saturation acts as a food “overcharge”. Food values will not decrease while the saturation is over zero. New players logging in or respawning automatically get a saturation of 5.0. Eating food increases the saturation as well as the food bar.
Packet ID State Bound To Field Name Field Type Notes
0x5D Play Client Health Float 0 or less = dead, 20 = full HP.
Food VarInt 0–20.
Food Saturation Float Seems to vary from 0.0 to 5.0 in integer increments.
Update Objectives
This is sent to the client when it should create a new scoreboard objective or remove one.
Packet ID State Bound To Field Name Field Type Notes
0x5E Play Client Objective Name String (32767) A unique name for the objective.
Mode Byte 0 to create the scoreboard. 1 to remove the scoreboard. 2 to update the display text.
Objective Value Optional Text Component Only if mode is 0 or 2.The text to be displayed for the score.
Type Optional VarInt Enum Only if mode is 0 or 2. 0 = "integer", 1 = "hearts".
Has Number Format Optional Boolean Only if mode is 0 or 2. Whether this objective has a set number format for the scores.
Number Format Optional VarInt Enum Only if mode is 0 or 2 and the previous boolean is true. Determines how the score number should be formatted.
Number Format Field Name
0: blank no fields Show nothing.
1: styled Styling Compound Tag The styling to be used when formatting the score number. Contains the text component styling fields.
2: fixed Content Text Component The text to be used as placeholder.
Set Passengers
Packet ID State Bound To Field Name Field Type Notes
0x5F Play Client Entity ID VarInt Vehicle's EID.
Passenger Count VarInt Number of elements in the following array.
Passengers Array of VarInt EIDs of entity's passengers.
Update Teams
Creates and updates teams.
Packet ID State Bound To Field Name Field Type Notes
0x60 Play Client Team Name String (32767) A unique name for the team. (Shared with scoreboard).
Method Byte Determines the layout of the remaining packet.
0: create team Team Display Name Text Component
Friendly Flags Byte Bit mask. 0x01: Allow friendly fire, 0x02: can see invisible players on same team.
Name Tag Visibility String Enum (40) always , hideForOtherTeams , hideForOwnTeam , never .
Collision Rule String Enum (40) always , pushOtherTeams , pushOwnTeam , never .
Team Color VarInt Enum Used to color the name of players on the team; see below.
Team Prefix Text Component Displayed before the names of players that are part of this team.
Team Suffix Text Component Displayed after the names of players that are part of this team.
Entity Count VarInt Number of elements in the following array.
Entities Array of String (32767) Identifiers for the entities in this team. For players, this is their username; for other entities, it is their UUID.
1: remove team no fields no fields
2: update team info Team Display Name Text Component
Friendly Flags Byte Bit mask. 0x01: Allow friendly fire, 0x02: can see invisible entities on same team.
Name Tag Visibility String Enum (40) always , hideForOtherTeams , hideForOwnTeam , never
Collision Rule String Enum (40) always , pushOtherTeams , pushOwnTeam , never
Team Color VarInt Enum Used to color the name of players on the team; see below.
Team Prefix Text Component Displayed before the names of players that are part of this team.
Team Suffix Text Component Displayed after the names of players that are part of this team.
3: add entities to team Entity Count VarInt Number of elements in the following array.
Entities Array of String (32767) Identifiers for the added entities. For players, this is their username; for other entities, it is their UUID.
4: remove entities from team Entity Count VarInt Number of elements in the following array.
Entities Array of String (32767) Identifiers for the removed entities. For players, this is their username; for other entities, it is their UUID.
Team Color: The color of a team defines how the names of the team members are visualized; any formatting code can be used. The following table lists all the possible values.
ID Formatting
0-15 Color formatting, same values as in Text formatting#Colors.
16 Obfuscated
17 Bold
18 Strikethrough
19 Underlined
20 Italic
21 Reset
Update Score
This is sent to the client when it should update a scoreboard item.
Packet ID State Bound To Field Name Field Type Notes
0x61 Play Client Entity Name String (32767) The entity whose score this is. For players, this is their username; for other entities, it is their UUID.
Objective Name String (32767) The name of the objective the score belongs to.
Value VarInt The score to be displayed next to the entry.
Has Display Name Boolean Whether this score has a custom display name.
Display Name Optional Text Component The custom display name. Only present if the previous boolean is true.
Has Number Format Boolean Whether this score has a set number format. This overrides the number format set on the objective, if any.
Number Format Optional VarInt Enum Determines how the score number should be formatted. Only present if the previous boolean is true.
Number Format Field Name
0: blank no fields Show nothing.
1: styled Styling Compound Tag The styling to be used when formatting the score number. Contains the text component styling fields.
2: fixed Content Text Component The text to be used as placeholder.
Set Simulation Distance
Packet ID State Bound To Field Name Field Type Notes
0x62 Play Client Simulation Distance VarInt The distance that the client will process specific things, such as entities.
Set Subtitle Text
Packet ID State Bound To Field Name Field Type Notes
0x63 Play Client Subtitle Text Text Component
Update Time
Time is based on ticks, where 20 ticks happen every second. There are 24000 ticks in a day, making Minecraft days exactly 20 minutes long.
The time of day is based on the timestamp modulo 24000. 0 is sunrise, 6000 is noon, 12000 is sunset, and 18000 is midnight.
The default SMP server increments the time by 20 every second.
Packet ID State Bound To Field Name Field Type Notes
0x64 Play Client World Age Long In ticks; not changed by server commands.
Time of day Long The world (or region) time, in ticks. If negative the sun will stop moving at the Math.abs of the time.
Set Title Text
Packet ID State Bound To Field Name Field Type Notes
0x65 Play Client Title Text Text Component
Set Title Animation Times
Packet ID State Bound To Field Name Field Type Notes
0x66 Play Client Fade In Int Ticks to spend fading in.
Stay Int Ticks to keep the title displayed.
Fade Out Int Ticks to spend fading out, not when to start fading out.
Entity Sound Effect
Plays a sound effect from an entity, either by hardcoded ID or Identifier. Sound IDs and names can be found here.
Numeric sound effect IDs are liable to change between versions
Packet ID State Bound To Field Name Field Type Notes
0x67 Play Client Sound ID VarInt Represents the Sound ID + 1 . If the value is 0, the packet contains a sound specified by Identifier.
Sound Name Optional Identifier Only present if Sound ID is 0
Has Fixed Range Optional Boolean Only present if Sound ID is 0.
Range Optional Float The fixed range of the sound. Only present if previous boolean is true and Sound ID is 0.
Sound Category VarInt Enum The category that this sound will be played from (current categories).
Entity ID VarInt
Volume Float 1.0 is 100%, capped between 0.0 and 1.0 by Notchian clients.
Pitch Float Float between 0.5 and 2.0 by Notchian clients.
Seed Long Seed used to pick sound variant.
Sound Effect
Plays a sound effect at the given location, either by hardcoded ID or Identifier. Sound IDs and names can be found here.
Numeric sound effect IDs are liable to change between versions
Packet ID State Bound To Field Name Field Type Notes
0x68 Play Client Sound ID VarInt Represents the Sound ID + 1 . If the value is 0, the packet contains a sound specified by Identifier.
Sound Name Optional Identifier Only present if Sound ID is 0
Has Fixed Range Optional Boolean Only present if Sound ID is 0.
Range Optional Float The fixed range of the sound. Only present if previous boolean is true and Sound ID is 0.
Sound Category VarInt Enum The category that this sound will be played from (current categories).
Effect Position X Int Effect X multiplied by 8 (fixed-point number with only 3 bits dedicated to the fractional part).
Effect Position Y Int Effect Y multiplied by 8 (fixed-point number with only 3 bits dedicated to the fractional part).
Effect Position Z Int Effect Z multiplied by 8 (fixed-point number with only 3 bits dedicated to the fractional part).
Volume Float 1.0 is 100%, capped between 0.0 and 1.0 by Notchian clients.
Pitch Float Float between 0.5 and 2.0 by Notchian clients.
Seed Long Seed used to pick sound variant.
Start Configuration
Sent during gameplay in order to redo the configuration process. The client must respond with Acknowledge Configuration for the process to start.
Packet ID State Bound To Field Name Field Type Notes
0x69 Play Client no fields
This packet switches the connection state to configuration.
Stop Sound
Packet ID State Bound To Field Name Field Type Notes
0x6A Play Client Flags Byte Controls which fields are present.
Source Optional VarInt Enum Only if flags is 3 or 1 (bit mask 0x1). See below. If not present, then sounds from all sources are cleared.
Sound Optional Identifier Only if flags is 2 or 3 (bit mask 0x2). A sound effect name, see Custom Sound Effect. If not present, then all sounds are cleared.
Name Value
master 0
music 1
record 2
weather 3
block 4
hostile 5
neutral 6
player 7
ambient 8
voice 9
Store Cookie (play)
Stores some arbitrary data on the client, which persists between server transfers. The Notchian client only accepts cookies of up to 5 kiB in size.
Packet ID State Bound To Field Name Field Type Notes
0x6B Play Client Key Identifier The identifier of the cookie.
Payload Length VarInt Length of the following byte array.
Payload Byte Array (5120) The data of the cookie.
System Chat Message
Main article: Chat
Sends the client a raw system message.
Packet ID State Bound To Field Name Field Type Notes
0x6C Play Client Content Text Component Limited to 262144 bytes.
Overlay Boolean Whether the message is an actionbar or chat message. See also #Set Action Bar Text.
Set Tab List Header And Footer
This packet may be used by custom servers to display additional information above/below the player list. It is never sent by the Notchian server.
Packet ID State Bound To Field Name Field Type Notes
0x6D Play Client Header Text Component To remove the header, send a empty text component: .
Footer Text Component To remove the footer, send a empty text component: .
Tag Query Response
Packet ID State Bound To Field Name Field Type Notes
0x6E Play Client Transaction ID VarInt Can be compared to the one sent in the original query packet.
NBT NBT The NBT of the block or entity. May be a TAG_END (0) in which case no NBT is present.
Pickup Item
Sent by the server when someone picks up an item lying on the ground — its sole purpose appears to be the animation of the item flying towards you. It doesn't destroy the entity in the client memory, and it doesn't add it to your inventory. The server only checks for items to be picked up after each Set Player Position (and Set Player Position And Rotation) packet sent by the client. The collector entity can be any entity; it does not have to be a player. The collected entity also can be any entity, but the Notchian server only uses this for items, experience orbs, and the different varieties of arrows.
Packet ID State Bound To Field Name Field Type Notes
0x6F Play Client Collected Entity ID VarInt
Collector Entity ID VarInt
Pickup Item Count VarInt Seems to be 1 for XP orbs, otherwise the number of items in the stack.
Teleport Entity
This packet is sent by the server when an entity moves more than 8 blocks.
Packet ID State Bound To Field Name Field Type Notes
0x70 Play Client Entity ID VarInt
X Double
Y Double
Z Double
Yaw Angle (Y Rot)New angle, not a delta.
Pitch Angle (X Rot)New angle, not a delta.
On Ground Boolean
Set Ticking State
Used to adjust the ticking rate of the client, and whether it's frozen.
Packet ID State Bound To Field Name Field Type Notes
0x71 Play Client Tick rate Float
Is frozen Boolean
Step Tick
Advances the client processing by the specified number of ticks. Has no effect unless client ticking is frozen.
Packet ID State Bound To Field Name Field Type Notes
0x72 Play Client Tick steps VarInt
Transfer (play)
Notifies the client that it should transfer to the given server. Cookies previously stored are preserved between server transfers.
Packet ID State Bound To Field Name Field Type Notes
0x73 Play Client Host String The hostname of IP of the server.
Port VarInt The port of the server.
Update Advancements
Packet ID State Bound To Field Name Field Type Notes
0x74 Play Client Reset/Clear Boolean Whether to reset/clear the current advancements.
Mapping size VarInt Size of the following array.
Advancement mapping Key Array Identifier The identifier of the advancement.
Value Advancement See below
List size VarInt Size of the following array.
Identifiers Array of Identifier The identifiers of the advancements that should be removed.
Progress size VarInt Size of the following array.
Progress mapping Key Array Identifier The identifier of the advancement.
Value Advancement progress See below.
Field Name Field Type Notes
Has parent Boolean Indicates whether the next field exists.
Parent id Optional Identifier The identifier of the parent advancement.
Has display Boolean Indicates whether the next field exists.
Display data Optional Advancement display See below.
Array length VarInt Number of arrays in the following array.
Requirements Array length 2 Array VarInt Number of elements in the following array.
Requirement Array of String (32767) Array of required criteria.
Sends telemetry data Boolean Whether the client should include this achievement in the telemetry data when it's completed.
The Notchian client only sends data for advancements on the minecraft namespace.
Field Name Field Type Notes
Title Text Component
Description Text Component
Icon Slot
Frame type VarInt Enum 0 = task , 1 = challenge , 2 = goal .
Flags Int 0x01: has background texture; 0x02: show_toast ; 0x04: hidden .
Background texture Optional Identifier Background texture location. Only if flags indicates it.
X coord Float
Y coord Float
Field Name Field Type Notes
Size VarInt Size of the following array.
Criteria Criterion identifier Array Identifier The identifier of the criterion.
Criterion progress Criterion progress
Field Name Field Type Notes
Achieved Boolean If true, next field is present.
Date of achieving Optional Long As returned by Date.getTime .
Update Attributes
Sets attributes on the given entity.
Packet ID State Bound To Field Name Field Type Notes
0x75 Play Client Entity ID VarInt
Number Of Properties VarInt Number of elements in the following array.
Property Id Array VarInt Enum See below.
Value Double See below.
Number Of Modifiers VarInt Number of elements in the following array.
Modifiers Array of Modifier Data See Attribute#Modifiers . Modifier Data defined below.
Id Key Default Min Max Label
0 generic.armor 0.0 0.0 30.0 Armor.
1 generic.armor_toughness 0.0 0.0 20.0 Armor Toughness.
2 generic.attack_damage 2.0 0.0 2048.0 Attack Damage.
3 generic.attack_knockback 0.0 0.0 5.0 Attack Knockback.
4 generic.attack_speed 4.0 0.0 1024.0 Attack Speed.
5 generic.block_break_speed 1.0 0.0 1024.0 Block Break Speed.
6 generic.block_interaction_range 4.5 0.0 64.0 Block Interaction Range.
7 generic.entity_interaction_range 3.0 0.0 64.0 Entity Interaction Range.
8 generic.fall_damage_multiplier 1.0 0.0 100.0 Fall Damage Multiplier.
9 generic.flying_speed 0.4 0.0 1024.0 Flying Speed.
10 generic.follow_range 32.0 0.0 2048.0 Follow Range.
11 generic.gravity 0.08 -1.0 1.0 Gravity.
12 generic.jump_strength 0.42 0.0 32.0 Jump Strength.
13 generic.knockback_resistance 0.0 0.0 1.0 Knockback Resistance.
14 generic.luck 0.0 -1024.0 1024.0 Luck.
15 generic.max_absorption 0.0 0.0 2048.0 Max Absorption.
16 generic.max_health 20.0 1.0 1024.0 Max Health.
17 generic.movement_speed 0.7 0.0 1024.0 Movement Speed.
18 generic.safe_fall_distance 3.0 -1024.0 1024.0 Safe Fall Distance.
19 generic.scale 1.0 0.0625 16.0 Scale.
20 zombie.spawn_reinforcements 0.0 0.0 1.0 Spawn Reinforcements Chance.
21 generic.step_height 0.6 0.0 10.0 Step Height.
22 generic.submerged_mining_speed 0.2 0.0 20.0 Submerged Mining Speed.
23 generic.sweeping_damage_ratio 0.0 0.0 1.0 Sweeping Damage Ratio.
24 generic.water_movement_efficiency 0.0 0.0 1.0 Water Movement Efficiency.
Modifier Data structure:
Field Name Field Type Notes
Id Identifier
Amount Double May be positive or negative.
Operation Byte See below.
The operation controls how the base value of the modifier is changed.

0: Add/subtract amount
1: Add/subtract amount percent of the current value
2: Multiply by amount percent

All of the 0's are applied first, and then the 1's, and then the 2's.
Entity Effect
Packet ID State Bound To Field Name Field Type Notes
0x76 Play Client Entity ID VarInt
Effect ID VarInt See this table .
Amplifier VarInt Notchian client displays effect level as Amplifier + 1.
Duration VarInt Duration in ticks. (-1 for infinite)
Flags Byte Bit field, see below.
The following information needs to be added to this page:
What exact effect does the blend bit flag have on the client? What happens if it is used on effects besides DARKNESS?

0x01: Is ambient - was the effect spawned from a beacon? All beacon-generated effects are ambient. Ambient effects use a different icon in the HUD (blue border rather than gray). If all effects on an entity are ambient, the "Is potion effect ambient" living metadata field should be set to true. Usually should not be enabled.
0x02: Show particles - should all particles from this effect be hidden? Effects with particles hidden are not included in the calculation of the effect color, and are not rendered on the HUD (but are still rendered within the inventory). Usually should be enabled.
0x04: Show icon - should the icon be displayed on the client? Usually should be enabled.
0x08: Blend - should the effect's hard-coded blending be applied? Currently only used in the DARKNESS effect to apply extra void fog and adjust the gamma value for lighting.

Update Recipes
Packet ID State Bound To Field Name Field Type Notes
0x77 Play Client Num Recipes VarInt Number of elements in the following array.
Recipe Recipe ID Array Identifier
Type ID VarInt Enum The recipe type, see below.
Data Varies Additional data for the recipe.
ID Type Description Data
0 minecraft:crafting_shaped Shaped crafting recipe. All items must be present in the same pattern (which may be flipped horizontally or translated). As follows:
Name Type Description
Group String (32767) Used to group similar recipes together in the recipe book. Tag is present in recipe JSON.
Category VarInt Enum Building = 0, Redstone = 1, Equipment = 2, Misc = 3
Width VarInt
Height VarInt
Ingredients Array of Ingredient Length is width * height . Indexed by x + (y * width) .
Result Slot
Show notification Boolean Show a toast when the recipe is added.
Name Type Description
Group String (32767) Used to group similar recipes together in the recipe book. Tag is present in recipe JSON.
Category VarInt Enum Building = 0, Redstone = 1, Equipment = 2, Misc = 3
Ingredient count VarInt Number of elements in the following array.
Ingredients Array of Ingredient.
Result Slot
Name Type Description
Category VarInt Enum Building = 0, Redstone = 1, Equipment = 2, Misc = 3
Name Type Description
Group String (32767) Used to group similar recipes together in the recipe book.
Category VarInt Enum Food = 0, Blocks = 1, Misc = 2
Ingredient Ingredient
Result Slot
Experience Float
Cooking time VarInt
Name Type Description
Group String (32767) Used to group similar recipes together in the recipe book. Tag is present in recipe JSON.
Ingredient Ingredient
Result Slot
Name Type Description
Template Ingredient The smithing template.
Base Ingredient The base item.
Addition Ingredient The additional ingredient.
Result Slot
Name Type Description
Template Ingredient The smithing template.
Base Ingredient The base item.
Addition Ingredient The additional ingredient.
Ingredient is defined as:
Name Type Description
Count VarInt Number of elements in the following array.
Items Array of Slot Any item in this array may be used for the recipe. The count of each item should be 1.
Update Tags (play)
Packet ID State Bound To Field Name Field Type Notes
0x78 Play Client Length of the array VarInt
Array of tags Registry Array Identifier Registry identifier (Vanilla expects tags for the registries minecraft:block , minecraft:item , minecraft:fluid , minecraft:entity_type , and minecraft:game_event )
Array of Tag (See below)
Tag arrays look like:
Field Name Field Type Notes
Length VarInt Number of elements in the following array
Tags Tag name Array Identifier
Count VarInt Number of elements in the following array
Entries Array of VarInt Numeric IDs of the given type (block, item, etc.). This list replaces the previous list of IDs for the given tag. If some preexisting tags are left unmentioned, a warning is printed.
See Tag on the Minecraft Wiki for more information, including a list of vanilla tags.
Projectile Power
Packet ID State Bound To Field Name Field Type Notes
0x79 Play Client Entity ID VarInt
Power Double
Custom Report Details
Contains a list of key-value text entries that are included in any crash or disconnection report generated during connection to the server.
Packet ID State Bound To Field Name Field Type Notes
0x7A Play Client Details Count VarInt (32) The number of details in the following array.
Details Title Array String (128)
Description String (4096)
Server Links
This packet contains a list of links that the Notchian client will display in the menu available from the pause menu. Link labels can be built-in or custom (i.e., any text).
Packet ID State Bound To Field Name Field Type Notes
0x7B Play Client Links Count VarInt The number of links in the following array.
Links Is built-in Array Boolean Determines if the following label is built-in (from enum) or custom (text component).
Label VarInt Enum / Text Component See below.
URL String Valid URL.
ID Name Notes
0 Bug Report Displayed on connection error screen; included as a comment in the disconnection report.
1 Community Guidelines
2 Support
3 Status
4 Feedback
5 Community
6 Website
7 Forums
8 News
9 Announcements

Serverbound
Confirm Teleportation
Sent by client as confirmation of Synchronize Player Position.
Packet ID State Bound To Field Name Field Type Notes
0x00 Play Server Teleport ID VarInt The ID given by the Synchronize Player Position packet.
Query Block Entity Tag
Used when F3 + I is pressed while looking at a block.
Packet ID State Bound To Field Name Field Type Notes
0x01 Play Server Transaction ID VarInt An incremental ID so that the client can verify that the response matches.
Location Position The location of the block to check.
Change Difficulty
Must have at least op level 2 to use. Appears to only be used on singleplayer; the difficulty buttons are still disabled in multiplayer.
Packet ID State Bound To Field Name Field Type Notes
0x02 Play Server New difficulty Byte 0: peaceful, 1: easy, 2: normal, 3: hard .
Acknowledge Message
Packet ID State Bound To Field Name Field Type Notes
0x03 Play Server Message Count VarInt
Chat Command
Main article: Chat
Packet ID State Bound To Field Name Field Type Notes
0x04 Play Server Command String (32767) The command typed by the client.
Signed Chat Command
Main article: Chat
Packet ID State Bound To Field Name Field Type Notes
0x05 Play Server Command String (32767) The command typed by the client.
Timestamp Long The timestamp that the command was executed.
Salt Long The salt for the following argument signatures.
Array length VarInt Number of entries in the following array. The maximum length in Notchian server is 8.
Array of argument signatures Argument name Array (8) String (16) The name of the argument that is signed by the following signature.
Signature Byte Array (256) The signature that verifies the argument. Always 256 bytes and is not length-prefixed.
Message Count VarInt
Acknowledged Fixed BitSet (20)
Chat Message
Main article: Chat
Used to send a chat message to the server. The message may not be longer than 256 characters or else the server will kick the client.
The server will broadcast a Player Chat Message packet with Chat Type minecraft:chat to all players that haven't disabled chat (including the player that sent the message). See Chat#Processing chat for more information.
Packet ID State Bound To Field Name Field Type Notes
0x06 Play Server Message String (256)
Timestamp Long
Salt Long The salt used to verify the signature hash.
Has Signature Boolean Whether the next field is present.
Signature Optional Byte Array (256) The signature used to verify the chat message's authentication. When present, always 256 bytes and not length-prefixed.
Message Count VarInt
Acknowledged Fixed BitSet (20)
Player Session
Packet ID State Bound To Field Name Field Type Notes
0x07 Play Server Session Id UUID
Public Key Expires At Long The time the play session key expires in epoch milliseconds.
Public Key Length VarInt Length of the proceeding public key. Maximum length in Notchian server is 512 bytes.
Public Key Byte Array (512) A byte array of an X.509-encoded public key.
Key Signature Length VarInt Length of the proceeding key signature array. Maximum length in Notchian server is 4096 bytes.
Key Signature Byte Array (4096) The signature consists of the player UUID, the key expiration timestamp, and the public key data. These values are hashed using SHA-1 and signed using Mojang's private RSA key.
Chunk Batch Received
Notifies the server that the chunk batch has been received by the client. The server uses the value sent in this packet to adjust the number of chunks to be sent in a batch.
The Notchian server will stop sending further chunk data until the client acknowledges the sent chunk batch. After the first acknowledgement, the server adjusts this number to allow up to 10 unacknowledged batches.
Packet ID State Bound To Field Name Field Type Notes
0x08 Play Server Chunks per tick Float Desired chunks per tick.
Client Status
Packet ID State Bound To Field Name Field Type Notes
0x09 Play Server Action ID VarInt Enum See below
Action ID values:
Action ID Action Notes
0 Perform respawn Sent when the client is ready to complete login and when the client is ready to respawn after death.
1 Request stats Sent when the client opens the Statistics menu.
Client Information (play)
Sent when the player connects, or when settings are changed.
Packet ID State Bound To Field Name Field Type Notes
0x0A Play Server Locale String (16) e.g. en_GB .
View Distance Byte Client-side render distance, in chunks.
Chat Mode VarInt Enum 0: enabled, 1: commands only, 2: hidden. See Chat#Client chat mode for more information.
Chat Colors Boolean “Colors” multiplayer setting. Can the chat be colored?
Displayed Skin Parts Unsigned Byte Bit mask, see below.
Main Hand VarInt Enum 0: Left, 1: Right.
Enable text filtering Boolean Enables filtering of text on signs and written book titles. Currently always false (i.e. the filtering is disabled)
Allow server listings Boolean Servers usually list online players, this option should let you not show up in that list.
Displayed Skin Parts flags:

The most significant bit (bit 7, 0x80) appears to be unused.
Command Suggestions Request
Sent when the client needs to tab-complete a minecraft:ask_server suggestion type.
Packet ID State Bound To Field Name Field Type Notes
0x0B Play Server Transaction Id VarInt The id of the transaction that the server will send back to the client in the response of this packet. Client generates this and increments it each time it sends another tab completion that doesn't get a response.
Text String (32500) All text behind the cursor without the / (e.g. to the left of the cursor in left-to-right languages like English).
Acknowledge Configuration
Sent by the client upon receiving a Start Configuration packet from the server.
Packet ID State Bound To Field Name Field Type Notes
0x0C Play Server no fields
This packet switches the connection state to configuration.
Click Container Button
Used when clicking on window buttons. Until 1.14, this was only used by enchantment tables.
Packet ID State Bound To Field Name Field Type Notes
0x0D Play Server Window ID Byte The ID of the window sent by Open Screen.
Button ID Byte Meaning depends on window type; see below.
Window type ID Meaning
Enchantment Table 0 Topmost enchantment.
1 Middle enchantment.
2 Bottom enchantment.
Lectern 1 Previous page (which does give a redstone output).
2 Next page.
3 Take Book.
100+page Opened page number - 100 + number.
Stonecutter Recipe button number - 4*row + col. Depends on the item.
Loom Recipe button number - 4*row + col. Depends on the item.
Click Container
This packet is sent by the client when the player clicks on a slot in a window.
Packet ID State Bound To Field Name Field Type Notes
0x0E Play Server Window ID Unsigned Byte The ID of the window which was clicked. 0 for player inventory. The server ignores any packets targeting a Window ID other than the current one, including ignoring 0 when any other window is open.
State ID VarInt The last received State ID from either a Set Container Slot or a Set Container Content packet.
Slot Short The clicked slot number, see below.
Button Byte The button used in the click, see below.
Mode VarInt Enum Inventory operation mode, see below.
Length of the array VarInt Maximum value for Notchian server is 128 slots.
Array of changed slots Slot number Array (128) Short
Slot data Slot New data for this slot, in the client's opinion; see below.
Carried item Slot Item carried by the cursor. Has to be empty (item for drop mode, otherwise nothing will happen.
See Inventory for further information about how slots are indexed.
After performing the action, the server compares the results to the slot change information included in the packet, as applied on top of the server's view of the container's state prior to the action. For any slots that do not match, it sends Set Container Slot packets containing the correct results. If State ID does not match the last ID sent by the server, it will instead send a full Set Container Content to resynchronize the client.
When right-clicking on a stack of items, half the stack will be picked up and half left in the slot. If the stack is an odd number, the half left in the slot will be smaller of the amounts.
The distinct type of click performed by the client is determined by the combination of the Mode and Button fields.
Mode Button Slot Trigger
0 0 Normal Left mouse click
1 Normal Right mouse click
0 -999 Left click outside inventory (drop cursor stack)
1 -999 Right click outside inventory (drop cursor single item)
1 0 Normal Shift + left mouse click
1 Normal Shift + right mouse click (identical behavior)
2 0 Normal Number key 1
1 Normal Number key 2
2 Normal Number key 3
⋮ ⋮ ⋮
8 Normal Number key 9
⋮ ⋮ Button is used as the slot index (impossible in vanilla clients)
40 Normal Offhand swap key F
3 2 Normal Middle click, only defined for creative players in non-player inventories.
4 0 Normal* Drop key (Q) (* Clicked item is always empty)
1 Normal* Control + Drop key (Q) (* Clicked item is always empty)
5 0 -999 Starting left mouse drag
4 -999 Starting right mouse drag
8 -999 Starting middle mouse drag, only defined for creative players in non-player inventories.
1 Normal Add slot for left-mouse drag
5 Normal Add slot for right-mouse drag
9 Normal Add slot for middle-mouse drag, only defined for creative players in non-player inventories.
2 -999 Ending left mouse drag
6 -999 Ending right mouse drag
10 -999 Ending middle mouse drag, only defined for creative players in non-player inventories.
6 0 Normal Double click
1 Normal Pickup all but check items in reverse order (impossible in vanilla clients)
Starting from version 1.5, “painting mode” is available for use in inventory windows. It is done by picking up stack of something (more than 1 item), then holding mouse button (left, right or middle) and dragging held stack over empty (or same type in case of right button) slots. In that case client sends the following to server after mouse button release (omitting first pickup packet which is sent as usual):

packet with mode 5, slot -999, button (0 for left | 4 for right);
packet for every slot painted on, mode is still 5, button (1 | 5);
packet with mode 5, slot -999, button (2 | 6);

If any of the painting packets other than the “progress” ones are sent out of order (for example, a start, some slots, then another start; or a left-click in the middle) the painting status will be reset.
Close Container
This packet is sent by the client when closing a window.
Notchian clients send a Close Window packet with Window ID 0 to close their inventory even though there is never an Open Screen packet for the inventory.
Packet ID State Bound To Field Name Field Type Notes
0x0F Play Server Window ID Unsigned Byte This is the ID of the window that was closed. 0 for player inventory.
Change Container Slot State
This packet is sent by the client when toggling the state of a Crafter.
Packet ID State Bound To Field Name Field Type Notes
0x10 Play Server Slot ID VarInt This is the ID of the slot that was changed.
Window ID VarInt This is the ID of the window that was changed.
State Boolean The new state of the slot. True for enabled, false for disabled.
Cookie Response (play)
Response to a Cookie Request (play) from the server. The Notchian server only accepts responses of up to 5 kiB in size.
Packet ID State Bound To Field Name Field Type Notes
0x11 Play Server Key Identifier The identifier of the cookie.
Has Payload Boolean The payload is only present if the cookie exists on the client.
Payload Length Optional VarInt Length of the following byte array.
Payload Optional Byte Array (5120) The data of the cookie, if any.
Serverbound Plugin Message (play)
Main article: Plugin channels
Mods and plugins can use this to send their data. Minecraft itself uses some plugin channels. These internal channels are in the minecraft namespace.
Note that the length of Data is known only from the packet length, since the packet has no length field of any kind.
Packet ID State Bound To Field Name Field Type Notes
0x12 Play Server Channel Identifier Name of the plugin channel used to send the data.
Data Byte Array (32767) Any data, depending on the channel. minecraft: channels are documented here. The length of this array must be inferred from the packet length.
In Notchian server, the maximum data length is 32767 bytes.
Debug Sample Subscription
Subscribes to the specified type of debug sample data, which is then sent periodically to the client via Debug Sample.
The Notchian server only allows subscriptions from players that are server operators.
Edit Book
Packet ID State Bound To Field Name Field Type Notes
0x14 Play Server Slot VarInt The hotbar slot where the written book is located
Count VarInt Number of elements in the following array. Maximum array size is 200.
Entries Array (200) of String (8192) Text from each page. Maximum string length is 8192 chars.
Has title Boolean If true, the next field is present. true if book is being signed, false if book is being edited.
Title Optional String (128) Title of book.
Query Entity Tag
Used when F3 + I is pressed while looking at an entity.
Packet ID State Bound To Field Name Field Type Notes
0x15 Play Server Transaction ID VarInt An incremental ID so that the client can verify that the response matches.
Entity ID VarInt The ID of the entity to query.
Interact
This packet is sent from the client to the server when the client attacks or right-clicks another entity (a player, minecart, etc).
A Notchian server only accepts this packet if the entity being attacked/used is visible without obstruction and within a 4-unit radius of the player's position.
The target X, Y, and Z fields represent the difference between the vector location of the cursor at the time of the packet and the entity's position.
Note that middle-click in creative mode is interpreted by the client and sent as a Set Creative Mode Slot packet instead.
Packet ID State Bound To Field Name Field Type Notes
0x16 Play Server Entity ID VarInt The ID of the entity to interact. Note the special case described below.
Type VarInt Enum 0: interact, 1: attack, 2: interact at.
Target X Optional Float Only if Type is interact at.
Target Y Optional Float Only if Type is interact at.
Target Z Optional Float Only if Type is interact at.
Hand Optional VarInt Enum Only if Type is interact or interact at; 0: main hand, 1: off hand.
Sneaking Boolean If the client is sneaking.
Interaction with the ender dragon is an odd special case characteristic of release deadline–driven design. 8 consecutive entity IDs following the dragon's ID ( id + 1, id + 2, . id + 8) are reserved for the 8 hitboxes that make up the dragon:
ID offset Description
0 The dragon itself (never used in this packet)
1 Head
2 Neck
3 Body
4 Tail 1
5 Tail 2
6 Tail 3
7 Wing 1
8 Wing 2
Jigsaw Generate
Sent when Generate is pressed on the Jigsaw Block interface.
Packet ID State Bound To Field Name Field Type Notes
0x17 Play Server Location Position Block entity location.
Levels VarInt Value of the levels slider/max depth to generate.
Keep Jigsaws Boolean
Serverbound Keep Alive (play)
The server will frequently send out a keep-alive (see Clientbound Keep Alive), each containing a random ID. The client must respond with the same packet.
Packet ID State Bound To Field Name Field Type Notes
0x18 Play Server Keep Alive ID Long
Lock Difficulty
Must have at least op level 2 to use. Appears to only be used on singleplayer; the difficulty buttons are still disabled in multiplayer.
Packet ID State Bound To Field Name Field Type Notes
0x19 Play Server Locked Boolean
Set Player Position
Updates the player's XYZ position on the server.
If the player is in a vehicle, the position is ignored (but in case of Set Player Position and Rotation, the rotation is still used as normal). No validation steps other than value range clamping are performed in this case.
If the player is sleeping, the position (or rotation) is not changed, and a Synchronize Player Position is sent if the received position deviated from the server's view by more than a meter.
The Notchian server silently clamps the x and z coordinates between -30,000,000 and 30,000,000, and the y coordinate between -20,000,000 and 20,000,000. A similar condition has historically caused a kick for "Illegal position"; this is no longer the case. However, infinite or NaN coordinates (or angles) still result in a kick for multiplayer.disconnect.invalid_player_movement .
As of 1.20.6, checking for moving too fast is achieved like this (sic):

Each server tick, the player's current position is stored.
When the player moves, the offset from the stored position to the requested position is computed (Δx, Δy, Δz).
The requested movement distance squared is computed as Δx² + Δy² + Δz².
The baseline expected movement distance squared is computed based on the player's server-side velocity as Vx² + Vy² + Vz². The player's server-side velocity is a somewhat ill-defined quantity that includes among other things gravity, jump velocity and knockback, but not regular horizontal movement. A proper description would bring much of Minecraft's physics engine with it. It is accessible as the Motion NBT tag on the player entity.
The maximum permitted movement distance squared is computed as 100 (300 if the player is using an elytra), multiplied by the number of movement packets received since the last tick, including this one, unless that value is greater than 5, in which case no multiplier is applied.
If the requested movement distance squared minus the baseline distance squared is more than the maximum squared, the player is moving too fast.

If the player is moving too fast, it is logged that " moved too quickly! " followed by the change in x, y, and z, and the player is teleported back to their current (before this packet) server-side position.
Checking for block collisions is achieved like this:

A temporary collision-checked move of the player is attempted from its current position to the requested one.
The offset from the resulting position to the requested position is computed. If the absolute value of the offset on the y axis is less than 0.5, it (only the y component) is rounded down to 0.
If the magnitude of the offset is greater than 0.25 and the player isn't in creative or spectator mode, it is logged that " moved wrongly!", and the player is teleported back to their current (before this packet) server-side position.
In addition, if the player's hitbox stationary at the requested position would intersect with a block, and they aren't in spectator mode, they are teleported back without a log message.

Checking for illegal flight is achieved like this:

When a movement packet is received, a flag indicating whether or not the player is floating mid-air is updated. The flag is set if the move test described above detected no collision below the player and the y component of the offset from the player's current position to the requested one is greater than -0.5, unless any of various conditions permitting flight (creative mode, elytra, levitation effect, etc., but not jumping) are met.
Each server tick, it is checked if the flag has been set for more than 80 consecutive ticks. If so, and the player isn't currently sleeping, dead or riding a vehicle, they are kicked for multiplayer.disconnect.flying .

Packet ID State Bound To Field Name Field Type Notes
0x1A Play Server X Double Absolute position.
Feet Y Double Absolute feet position, normally Head Y - 1.62.
Z Double Absolute position.
On Ground Boolean True if the client is on the ground, false otherwise.
Set Player Position and Rotation
Packet ID State Bound To Field Name Field Type Notes
0x1B Play Server X Double Absolute position.
Feet Y Double Absolute feet position, normally Head Y - 1.62.
Z Double Absolute position.
Yaw Float Absolute rotation on the X Axis, in degrees.
Pitch Float Absolute rotation on the Y Axis, in degrees.
On Ground Boolean True if the client is on the ground, false otherwise.

Field Name	Field Type	Meaning
Length	VarInt	Number of longs in the following array. May be 0 (if no bits are set).
Data	Array of Long	A packed representation of the bit set as created by BitSet.toLongArray .

Term	Definition
Player	When used in the singular, Player always refers to the client connected to the server.
Entity	Entity refers to any item, player, mob, minecart or boat etc. See the Minecraft Wiki article for a full list.
EID	An EID — or Entity ID — is a 4-byte sequence used to identify a specific entity. An entity's EID is unique on the entire server.
XYZ	In this document, the axis names are the same as those shown in the debug screen (F3). Y points upwards, X points east, and Z points south.
Meter	The meter is Minecraft's base unit of length, equal to the length of a vertex of a solid block. The term “block” may be used to mean “meter” or “cubic meter”.
Registry	A table describing static, gameplay-related objects of some kind, such as the types of entities, block states or biomes. The entries of a registry are typically associated with textual or numeric identifiers, or both.

Field Name	Field Type	Notes
Length	VarInt	Length of Packet ID + Data
Packet ID	VarInt
Data	Byte Array	Depends on the connection state and packet ID, see the sections below

Present?	Compressed?	Field Name	Field Type	Notes
always	No	Packet Length	VarInt	Length of (Data Length) + length of compressed (Packet ID + Data)
if size >= threshold	No	Data Length	VarInt	Length of uncompressed (Packet ID + Data)
	Yes	Packet ID	VarInt	zlib compressed packet ID (see the sections below)
	Yes	Data	Byte Array	zlib compressed packet data (see the sections below)
if size < threshold	No	Data Length	VarInt	0 to indicate uncompressed
		Packet ID	VarInt	packet ID (see the sections below)
		Data	Byte Array	packet data (see the sections below)

Packet ID	State	Bound To	Field Name	Field Type	Notes
0x00	Handshaking	Server	Protocol Version	VarInt	See protocol version numbers (currently 767 in Minecraft 1.21).
			Server Address	String (255)	Hostname or IP, e.g. localhost or 127.0.0.1, that was used to connect. The Notchian server does not use this information. Note that SRV records are a simple redirect, e.g. if _minecraft._tcp.example.com points to mc.example.org, users connecting to example.com will provide example.org as server address in addition to connecting to it.
			Server Port	Unsigned Short	Default is 25565. The Notchian server does not use this information.
			Next State	VarInt Enum	1 for Status, 2 for Login, 3 for Transfer.

Packet ID	State	Bound To	Field Name	Field Type	Notes
0x00	Status	Client
0x00	Status	Client	JSON Response	String (32767)	See Server List Ping#Status Response; as with all strings this is prefixed by its length as a VarInt.

Packet ID	State	Bound To	Field Name	Field Type	Notes
0x01	Login	Client	Server ID	String (20)	Appears to be empty.
			Public Key Length	VarInt	Length of Public Key.
			Public Key	Byte Array	The server's public key, in bytes.
			Verify Token Length	VarInt	Length of Verify Token. Always 4 for Notchian servers.
			Verify Token	Byte Array	A sequence of random bytes generated by the server.
			Should authenticate	Boolean	Whether the client should attempt to authenticate through mojang servers.

Packet ID	State	Bound To	Field Name	Field Type	Notes
0x04	Login	Client	Message ID	VarInt	Generated by the server - should be unique to the connection.
			Channel	Identifier	Name of the plugin channel used to send the data.
			Data	Byte Array (1048576)	Any data, depending on the channel. The length of this array must be inferred from the packet length.

Packet ID	State	Bound To	Field Name	Field Type	Notes
0x01	Configuration	Client	Channel	Identifier	Name of the plugin channel used to send the data.
0x01	Configuration	Client	Data	Byte Array (1048576)	Any data. The length of this array must be inferred from the packet length.

Packet ID	State	Bound To	Field Name		Field Type		Notes
0x07	Configuration	Client
			Registry ID		Identifier
			Entry Count		VarInt		Number of entries in the following array.
			Entries	Entry ID	Array	Identifier
				Has Data		Boolean	Whether the entry has any data following.
				Data		NBT	Entry data. Only present if Has Data is true.

Packet ID	State	Bound To	Field Name	Field Type	Notes
0x08	Configuration	Client	Has UUID	Boolean	Whether a specific resource pack should be removed, or all of them.
0x08	Configuration	Client	UUID	Optional UUID	The UUID of the resource pack to be removed. Only present if the previous field is true.

Packet ID	State	Bound To	Field Name	Field Type	Notes
0x09	Configuration	Client	UUID	UUID	The unique identifier of the resource pack.
			URL	String (32767)	The URL to the resource pack.
			Hash	String (40)	A 40 character hexadecimal, case-insensitive SHA-1 hash of the resource pack file. If it's not a 40 character hexadecimal string, the client will not use it for hash verification and likely waste bandwidth.
			Forced	Boolean	The Notchian client will be forced to use the resource pack from the server. If they decline they will be kicked from the server.
			Has Prompt Message	Boolean	Whether a custom message should be used on the resource pack prompt.
			Prompt Message	Optional Text Component	This is shown in the prompt making the client accept or decline the resource pack. Only present if the previous field is true.

Packet ID	State	Bound To	Field Name	Field Type	Notes
0x0A	Configuration	Client	Key	Identifier	The identifier of the cookie.
			Payload Length	VarInt	Length of the following byte array.
			Payload	Byte Array (5120)	The data of the cookie.

Packet ID	State	Bound To	Field Name		Field Type		Notes
0x0B	Configuration	Client	Host		String		The hostname or IP of the server.
0x0B	Configuration	Client	Port		VarInt		The port of the server.

Packet ID	State	Bound To	Field Name	Field Type	Notes
0x0C	Configuration	Client	Total Features	VarInt	Number of features that appear in the array below.
0x0C	Configuration	Client	Feature Flags	Array of Identifier

Packet ID	State	Bound To	Field Name		Field Type		Notes
0x0D	Configuration	Client	Length of the array		VarInt
			Array of tags	Registry	Array	Identifier	Registry identifier (Vanilla expects tags for the registries minecraft:block , minecraft:item , minecraft:fluid , minecraft:entity_type , and minecraft:game_event )
			Array of tags	Array of Tag	Array	(See below)

Field Name		Field Type		Notes
Length		VarInt		Number of elements in the following array
Tags	Tag name	Array	Identifier
	Count		VarInt	Number of elements in the following array
	Entries		Array of VarInt	Numeric IDs of the given type (block, item, etc.). This list replaces the previous list of IDs for the given tag. If some preexisting tags are left unmentioned, a warning is printed.

Packet ID	State	Bound To	Field Name		Field Type		Notes
0x0E	Configuration	Client	Known Pack Count		VarInt		The number of known packs in the following array.
			Known Packs	Namespace	Array	String
				ID		String
				Version		String

Packet ID	State	Bound To	Field Name		Field Type		Notes
0x0F	Configuration	Client	Details Count		VarInt (32)		The number of details in the following array.
			Details	Title	Array	String (128)
			Details	Description	Array	String (4096)

Packet ID	State	Bound To	Field Name		Field Type		Notes
0x10	Configuration	Client	Links Count		VarInt		The number of links in the following array.
			Links	Is built-in	Array	Boolean	True if Label is an enum (built-in label), false if it's a text component (custom label).
				Label		VarInt Enum / Text Component	See below.
				URL		String	Valid URL.

Protocol

Contents

Definitions

Data types

Identifier

VarInt and VarLong

Position

Fixed-point numbers

Bit sets

BitSet

Fixed BitSet

Other definitions

Packet format

Without compression

With compression

Handshaking

Clientbound

Serverbound

Handshake

Legacy Server List Ping

Status

Clientbound

Status Response

Pong Response (status)

Serverbound

Status Request

Ping Request (status)

Login

Clientbound

Disconnect (login)

Encryption Request

Login Success

Set Compression

Login Plugin Request

Cookie Request (login)

Serverbound

Login Start

Encryption Response

Login Plugin Response

Login Acknowledged

Cookie Response (login)

Configuration

Clientbound

Cookie Request (configuration)

Clientbound Plugin Message (configuration)

Disconnect (configuration)

Finish Configuration

Clientbound Keep Alive (configuration)

Ping (configuration)

Reset Chat

Registry Data

Remove Resource Pack (configuration)

Add Resource Pack (configuration)

Store Cookie (configuration)

Transfer (configuration)

Feature Flags

Update Tags (configuration)

Clientbound Known Packs

Custom Report Details (configuration)

Server Links (configuration)

Serverbound

Client Information (configuration)

Cookie Response (configuration)

Serverbound Plugin Message (configuration)

Acknowledge Finish Configuration

Serverbound Keep Alive (configuration)

Pong (configuration)

Resource Pack Response (configuration)

Serverbound Known Packs

Play

Clientbound

Bundle Delimiter

Spawn Entity

Spawn Experience Orb

Entity Animation

Award Statistics

Acknowledge Block Change

Set Block Destroy Stage

Block Entity Data

Block Action

ID	Name	Notes
0	Bug Report	Displayed on connection error screen; included as a comment in the disconnection report.
1	Community Guidelines
2	Support
3	Status
4	Feedback
5	Community
6	Website
7	Forums
8	News
9	Announcements

Packet ID	State	Bound To	Field Name	Field Type	Notes
0x06	Configuration	Server
			UUID	UUID	The unique identifier of the resource pack received in the Add Resource Pack (configuration) request.
			Result	VarInt Enum	Result ID (see below).

ID	Result
0	Successfully downloaded
1	Declined
2	Failed to download
3	Accepted
4	Downloaded
5	Invalid URL
6	Failed to reload
7	Discarded

Packet ID	State	Bound To	Field Name	Field Type	Notes
0x03	Play	Client	Entity ID	VarInt	Player ID.
0x03	Play	Client	Animation	Unsigned Byte	Animation ID (see below).

ID	Animation
0	Swing main arm
2	Leave bed
3	Swing offhand
4	Critical effect
5	Magic critical effect

Name	ID	Registry
minecraft.mined	0	Blocks
minecraft.crafted	1	Items
minecraft.used	2	Items
minecraft.broken	3	Items
minecraft.picked_up	4	Items
minecraft.dropped	5	Items
minecraft.killed	6	Entities
minecraft.killed_by	7	Entities
minecraft.custom	8	Custom

Name	ID	Unit
minecraft.leave_game	0	None
minecraft.play_one_minute	1	Time
minecraft.time_since_death	2	Time
minecraft.time_since_rest	3	Time
minecraft.sneak_time	4	Time
minecraft.walk_one_cm	5	Distance
minecraft.crouch_one_cm	6	Distance
minecraft.sprint_one_cm	7	Distance
minecraft.walk_on_water_one_cm	8	Distance
minecraft.fall_one_cm	9	Distance
minecraft.climb_one_cm	10	Distance
minecraft.fly_one_cm	11	Distance
minecraft.walk_under_water_one_cm	12	Distance
minecraft.minecart_one_cm	13	Distance
minecraft.boat_one_cm	14	Distance
minecraft.pig_one_cm	15	Distance
minecraft.horse_one_cm	16	Distance
minecraft.aviate_one_cm	17	Distance
minecraft.swim_one_cm	18	Distance
minecraft.strider_one_cm	19	Distance
minecraft.jump	20	None
minecraft.drop	21	None
minecraft.damage_dealt	22	Damage
minecraft.damage_dealt_absorbed	23	Damage
minecraft.damage_dealt_resisted	24	Damage
minecraft.damage_taken	25	Damage
minecraft.damage_blocked_by_shield	26	Damage
minecraft.damage_absorbed	27	Damage
minecraft.damage_resisted	28	Damage
minecraft.deaths	29	None
minecraft.mob_kills	30	None
minecraft.animals_bred	31	None
minecraft.player_kills	32	None
minecraft.fish_caught	33	None
minecraft.talked_to_villager	34	None
minecraft.traded_with_villager	35	None
minecraft.eat_cake_slice	36	None
minecraft.fill_cauldron	37	None
minecraft.use_cauldron	38	None
minecraft.clean_armor	39	None
minecraft.clean_banner	40	None
minecraft.clean_shulker_box	41	None
minecraft.interact_with_brewingstand	42	None
minecraft.interact_with_beacon	43	None
minecraft.inspect_dropper	44	None
minecraft.inspect_hopper	45	None
minecraft.inspect_dispenser	46	None
minecraft.play_noteblock	47	None
minecraft.tune_noteblock	48	None
minecraft.pot_flower	49	None
minecraft.trigger_trapped_chest	50	None
minecraft.open_enderchest	51	None
minecraft.enchant_item	52	None
minecraft.play_record	53	None
minecraft.interact_with_furnace	54	None
minecraft.interact_with_crafting_table	55	None
minecraft.open_chest	56	None
minecraft.sleep_in_bed	57	None
minecraft.open_shulker_box	58	None
minecraft.open_barrel	59	None
minecraft.interact_with_blast_furnace	60	None
minecraft.interact_with_smoker	61	None
minecraft.interact_with_lectern	62	None
minecraft.interact_with_campfire	63	None
minecraft.interact_with_cartography_table	64	None
minecraft.interact_with_loom	65	None
minecraft.interact_with_stonecutter	66	None
minecraft.bell_ring	67	None
minecraft.raid_trigger	68	None
minecraft.raid_win	69	None
minecraft.interact_with_anvil	70	None
minecraft.interact_with_grindstone	71	None
minecraft.target_hit	72	None
minecraft.interact_with_smithing_table	73	None

Packet ID	State	Bound To	Field Name	Field Type	Notes
0x11	Play	Client	Count	VarInt	Number of elements in the following array.
			Nodes	Array of Node	An array of nodes.
			Root index	VarInt	Index of the root node in the previous array.

Packet ID	State	Bound To	Field Name	Field Type	Notes
0x13	Play	Client	Window ID	Unsigned Byte	The ID of window which items are being sent for. 0 for player inventory. The client ignores any packets targeting a Window ID other than the current one. However, an exception is made for the player inventory, which may be targeted at any time. (The Notchian server does not appear to utilize this special case.)
			State ID	VarInt	A server-managed sequence number used to avoid desynchronization; see #Click Container.
			Count	VarInt	Number of elements in the following array.
			Slot Data	Array of Slot
			Carried Item	Slot	Item being dragged with the mouse.

Packet ID	State	Bound To	Field Name	Field Type	Notes
0x14	Play	Client	Window ID	Unsigned Byte
			Property	Short	The property to be updated, see below.
			Value	Short	The new value for the property, see below.