Protocol
This page presents a dissection of the current stable Minecraft protocol. The current pre-release protocol is documented elsewhere.
Credit goes to the Great Old Ones, and the citizens of #mcdevs who helped by providing packet dumps and insight. If you're having trouble, check out the FAQ. Make sure you check the Data Types page.
Note: While you may use the contents of this page without restriction to create servers, clients, bots, etc… you still need to provide the attribution above if you copy any of the contents of this page for publication elsewhere.
The protocol for Pocket Minecraft is substantially different, and is documented at Pocket Minecraft Protocol.
Additionally, the minecraft server supports two other protocols since beta 1.9pre4, Rcon (for remote administration) and Query (to query server properties). With the default settings, they listen on TCP 25575 and UDP 25565 respectively.
This is a fairly lengthy page, and to make it more readable certain terminology must be understood. Terms used on this page and their definition are provided below.
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 in the world. This definition is subject to change as Notch extends the protocol |
EID | An EID - or Entity ID - is a unique 4-byte integer used to identify a specific entity |
XYZ | In this document, the axis names are the same as those used by Notch. Y points upwards, X points South, and Z points West. |
Plugin Channels
Plugin channels (present in 0xFA) are used to supplement the protocol. Information about these channels can be found at their page: plugin channel
Packets
All packets begin with a single "Packet ID" byte. Listed packet size includes this byte. Packets are either "server to client", "client to server", or both. If not specified, assume that the packet can be sent both ways. There is no "length" field; for variable length packets, you must parse to the end to determine the length.
Keep Alive (0x00)
Two-Way
The server will frequently send out a keep-alive, each containing a random ID. The client must respond with the same packet. The Beta server will disconnect a client if it doesn't receive at least one packet before 1200 in-game ticks, and the Beta client will time out the connection under the same conditions. The client may send packets with Keep-alive ID=0.
Packet ID | Field Name | Field Type | Example | Notes |
0x00 | Keep-alive ID | int | 957759560
|
Server-generated random id |
Total Size: | 5 bytes |
Login Request (0x01)
Server to Client
See Protocol Encryption for information on logging in.
Packet ID | Field Name | Field Type | Example | Notes |
0x01 | Entity ID | int | 1298
|
The Player's Entity ID |
Level type | string | default | default , flat , or largeBiomes . level-type in server.properties
| |
Game mode | byte | 0
|
0 : survival, 1 : creative, 2 : adventure. Bit 3 (0x8 ) is the hardcore flag
| |
Dimension | byte | 0
|
-1 : nether, 0 : overworld, 1 : end
| |
Difficulty | byte | 1
|
0 thru 3 for Peaceful, Easy, Normal, Hard
| |
Not used | byte | 0
|
Only 0 observed from vanilla server, was previously world height | |
Max players | byte | 8
|
Used by the client to draw the player list | |
Total Size: | 12 bytes + length of strings |
Handshake (0x02)
Client to server
See Protocol Encryption for information on logging in.
Packet ID | Field Name | Field Type | Example | Notes |
0x02 | Protocol Version | byte | 47
|
As of 1.4.2 the protocol version is 47 |
Username | string | _AlexM
|
The username of the player attempting to connect | |
Server Host | string | localhost
|
||
Server Port | int | 25565
|
||
Total Size: | 10 bytes + length of strings |
Chat Message (0x03)
Two-Way
The default server will check the message to see if it begins with a '/'. If it doesn't, the username of the sender is prepended and sent to all other clients (including the original sender). If it does, the server assumes it to be a command and attempts to process it. A message longer than 100 characters will cause the server to kick the client. (As of 1.3.2, the vanilla client appears to limit the text a user can enter to 100 charaters.) This limits the chat message packet length to 103 bytes. Note that this limit does not apply to incoming chat messages as the server may have prepended other information, not limited to, but usually including, a username.
A message longer than 119 characters will cause the server and client to print the message "Received string length longer than maximum allowed (X > 119)", with no side effects.
For more information, see Chat.
Packet ID | Field Name | Field Type | Example | Notes |
0x03 | Message | string | <Bob> Hello World!
|
User input must be sanitized server-side |
Total Size: | 3 bytes + length of strings |
Time Update (0x04)
Server to Client
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 | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0x04 | Age of the world | long | 45464654 | In ticks; not changed by server commands |
Time of Day | long | 21321 | The world (or region) time, in ticks | |
Total Size: | 17 Bytes |
Entity Equipment (0x05)
Server to Client
Packet ID | Field Name | Field Type | Example | Notes |
0x05 | Entity ID | int | 0x00010643 | Named Entity ID |
Slot | short | 4 | Equipment slot: 0=held, 1-4=armor slot | |
Item | slot | Item in slot format | ||
Total Size: | 7 bytes + slot data |
Spawn Position (0x06)
Server to Client
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.
Packet ID | Field Name | Field Type | Example | Notes |
0x06 | X | int | 117
|
Spawn X in block coordinates |
Y | int | 70
|
Spawn Y in block coordinates | |
Z | int | -46
|
Spawn Z in block coordinates | |
Total Size: | 13 bytes |
Use Entity (0x07)
Client to Server
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.
Packet ID | Field Name | Field Type | Example | Notes |
0x07 | User | int | 1298
|
The entity of the player (ignored by the server) |
Target | int | 1805
|
The entity the player is interacting with | |
Mouse button | boolean | true
|
true when the player is left-clicking and false when right-clicking.
| |
Total Size: | 10 bytes |
Update Health (0x08)
Server to Client
Sent by the server to update/set the health of the player it is sent to. Added in protocol version 5.
Food saturation acts as a food "overcharge". Food values will not decrease while the saturation is over zero. Players logging in automatically get a saturation of 5.0. Eating food increases the saturation as well as the food bar.
Packet ID | Field Name | Field Type | Example | Notes |
0x08 | Health | short | 20 | 0 or less = dead, 20 = full HP |
Food | short | 20 | 0 - 20 | |
Food Saturation | float | 5.0 | Seems to vary from 0.0 to 5.0 in integer increments | |
Total Size: | 9 bytes |
Respawn (0x09)
Server to Client
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 | Field Name | Field Type | Example | Notes |
0x09 | Dimension | int | 1
|
-1 : The Nether, 0 : The Overworld, 1 : The End
|
Difficulty | byte | 1
|
0 thru 3 for Peaceful, Easy, Normal, Hard. 1 is always sent c->s
| |
Game mode | byte | 1
|
0 : survival, 1 : creative, 2 : adventure. The hardcore flag is not included
| |
World height | short | 256
|
Defaults to 256
| |
Level type | string | default | See 0x01 login | |
Total Size: | 11 bytes + length of string |
Player (0x0A)
Client to Server
This packet is used to indicate whether the player is on ground (walking/swimming), or airborne (jumping/falling).
When dropping from sufficient height, fall damage is applied when this state goes from False to True. The amount of damage applied is based on the point where it last changed from True to False. Note that there are several movement related packets containing this state.
This packet was previously referred to as Flying
Packet ID | Field Name | Field Type | Example | Notes |
0x0A | On Ground | boolean | 1
|
True if the client is on the ground, False otherwise
|
Total Size: | 2 bytes |
Player Position (0x0B)
Client to Server
Updates the players XYZ position on the server.
If Stance - Y
is less than 0.1
or greater than 1.65
,
the stance is illegal and the client will be kicked with the message
“Illegal Stance”.
If the distance between the last known position of the player on the
server and the new position set by this packet is greater than 100 units
will result in the client being kicked for "You moved too
quickly :( (Hacking?)"
Also if the absolute number of X or Z is set greater than 3.2E7D
the client will be kicked for "Illegal position"
Packet ID | Field Name | Field Type | Example | Notes |
0x0B | X | double | 102.809
|
Absolute position |
Y | double | 70.00
|
Absolute position | |
Stance | double | 71.62
|
Used to modify the players bounding box when going up stairs, crouching, etc… | |
Z | double | 68.30
|
Absolute position | |
On Ground | boolean | 1
|
Derived from packet 0x0A | |
Total Size: | 34 bytes |
Player Look (0x0C)
Client to Server
Updates the direction the player is looking in.
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 backwards towards (-1, 0), or in other words, it turns clockwise instead of counterclockwise. Additionally, yaw is not clamped to between 0 and 360 degrees; any number is valid, including negative numbers and numbers greater than 360.
Pitch is measured in degrees, where 0 is looking straight ahead, -90 is looking straight up, and 90 is looking straight down.
You can get a unit vector from a given yaw/pitch via:
x = -cos(pitch) * sin(yaw) y = -sin(pitch) z = cos(pitch) * cos(yaw)
Packet ID | Field Name | Field Type | Example | Notes |
0x0C | Yaw | float | 0.00
|
Absolute rotation on the X Axis, in degrees |
Pitch | float | 0.00
|
Absolute rotation on the Y Axis, in degrees | |
On Ground | boolean | 1
|
Derived from packet 0x0A | |
Total Size: | 10 bytes |
Player Position and Look (0x0D)
Two-Way
A combination of Player Look and Player position.
Client to Server
Packet ID | Field Name | Field Type | Example | Notes |
0x0D | X | double | 6.5
|
Absolute position |
Y | double | 65.620000004768372
|
Absolute position | |
Stance | double | 67.240000009536743
|
Used to modify the players bounding box when going up stairs, crouching, etc… | |
Z | double | 7.5
|
Absolute position | |
Yaw | float | 0.0
|
Absolute rotation on the X Axis | |
Pitch | float | 0.0
|
Absolute rotation on the Y Axis | |
On Ground | boolean | 0
|
Derived from packet 0x0A | |
Total Size: | 42 bytes |
Server to Client
Packet ID | Field Name | Field Type | Example | Notes |
0x0D | X | double | 6.5
|
Absolute position |
Stance | double | 67.240000009536743
|
Used to modify the players bounding box when going up stairs, crouching, etc… | |
Y | double | 65.620000004768372
|
Absolute position | |
Z | double | 7.5
|
Absolute position | |
Yaw | float | 0.0
|
Absolute rotation on the X Axis | |
Pitch | float | 0.0
|
Absolute rotation on the Y Axis | |
On Ground | boolean | 0
|
Derived from packet 0x0A | |
Total Size: | 42 bytes |
Note that this packet differs from client Player & Position Look packet - the Stance and Y are sent in a different order.
Stance and Y seems to be the opposite as in the table (from Client to Server = X, Y, Stance, Z, from Server to client = X, Stance, Y, Z) please confirm ! [BackBone`:] The opposite stance<->y confirmed, however the given structs had the server and client struct reversed, which I fixed.
When you connect to the official server, it will push a 0x0D packet. If you do not immediately respond with a 0x0D (or maybe 0x0A-0x0C) packet with similar and valid information, it will have unexpected results, such as map chunks not loading and future 0x0A-0x0D packets being ignored.
Player Digging (0x0E)
Client to Server
Sent when the player mines a block. A Notchian server only accepts digging packets with coordinates within a 6-unit radius of the player's position.
Packet ID | Field Name | Field Type | Example | Notes |
0x0E | Status | byte | 1
|
The action the player is taking against the block (see below) |
X | int | 32
|
Block position | |
Y | byte | 64
|
Block position | |
Z | int | 32
|
Block position | |
Face | byte | 3
|
The face being hit (see below) | |
Total Size: | 12 bytes |
Status can (currently) be one of six values:
Meaning | Value |
Started digging | 0
|
Cancelled digging | 1
|
Finished digging | 2
|
Check block | 3
|
Drop item | 4
|
Shoot arrow / finish eating | 5
|
Notchian clients send a 0 (started digging) when they start digging and a 2 (finished digging) once they think they are finished. If digging is aborted, no notice is sent to the server; the client simply does not send a 2 (finished digging).
Status code 3 is never sent by a Notchian client, but it is supported by Notchian servers. If the block coordinates are within a 16-unit radius of the player's position, the server responds with a Block Change packet containing that block's current type and metadata. No actual changes occur to the world in this case.
Status code 4 (drop item) is a special case. In-game, when you use the Drop Item command (keypress 'q'), a dig packet with a status of 4, and all other values set to 0, is sent from client to server.
Status code 5 (shoot arrow / finish eating) is also a special case. The x, y and z fields are all set to 0 like above, with the exception of the face field, which is set to 255.
The face can be one of six values, representing the face being hit:
Value | 0 | 1 | 2 | 3 | 4 | 5 |
Offset | -Y | +Y | -Z | +Z | -X | +X |
In 1.7.3, when a player opens a door with left click the server receives Packet 0xE+start digging and opens the door.
Player Block Placement (0x0F)
Client to Server
Packet ID | Field Name | Field Type | Example | Notes |
0x0F | X | int | 32
|
Block position |
Y | unsigned byte | 64
|
Block position | |
Z | int | 32
|
Block position | |
Direction | byte | 3
|
The offset to use for block/item placement (see below) | |
Held item | slot | |||
Cursor position X | byte | 0 - 16 | The position of the crosshair on the block | |
Cursor position Y | byte | 0 - 16 | ||
Cursor position Z | byte | 0 - 16 | ||
Total Size: | 14 bytes + slot data |
In normal operation (ie placing a block), this packet is sent once, with the values set normally.
This packet has a special case where X, Y, Z, and Direction are all -1. (Note that Y is unsigned so set to 255.) This special packet indicates that the currently held item for the player should have its state updated such as eating food, shooting bows, using buckets, etc.
In a Notchian Beta client, the block or item ID corresponds to whatever the client is currently holding, and the client sends one of these packets any time a right-click is issued on a surface, so no assumptions can be made about the safety of the ID. However, with the implementation of server-side inventory, a Notchian server seems to ignore the item ID, instead operating on server-side inventory information and holding selection. The client has been observed (1.2.5 and 1.3.2) to send both real item IDs and -1 in a single session.
Special note on using buckets: When using buckets, the Notchian client might send two packets: first a normal and then a special case. The first normal packet is sent when you're looking at a block (e.g. the water you want to scoop up). This normal packet does not appear to do anything with a Notchian server. The second, special case packet appears to perform the action - based on current position/orientation and with a distance check - it appears that buckets can only be used within a radius of 6 units.
Held Item Change (0x10)
Client to Server
Sent when the player changes the slot selection
Packet ID | Field Name | Field Type | Example | Notes |
0x10 | Slot ID | short | 1
|
The slot which the player has selected (0-8) |
Total Size: | 3 bytes |
Use Bed (0x11)
Server to Client
This packet tells that a player goes to bed.
The client with the matching Entity ID will go into bed mode.
This Packet is sent to all nearby players including the one sent to bed.
Packet ID | Field Name | Field Type | Example | Notes |
0x11 | Entity ID | int | 89 | Player ID |
Unknown | byte | 0 | Only 0 has been observed | |
X coordinate | int | -247 | Bed headboard X as block coordinate | |
Y coordinate | byte | 78 | Bed headboard Y as block coordinate | |
Z coordinate | int | 128 | Bed headboard Z as block coordinate | |
Total Size: | 15 bytes |
Animation (0x12)
Two-Way
Sent whenever an entity should change animation.
Packet ID | Field Name | Field Type | Example | Notes |
0x12 | EID | int | 55534
|
Player ID |
Animation | byte | 1
|
Animation ID | |
Total Size: | 6 bytes |
Animation can be one of the following values:
ID | Animation |
---|---|
0 | No animation |
1 | Swing arm |
2 | Damage animation |
3 | Leave bed |
5 | Eat food |
102 | (unknown) |
104 | Crouch |
105 | Uncrouch |
Only 1
(swing arm) is sent by notchian clients.
Crouching is sent via 0x13. Damage is server-side, and so is not sent by
notchian clients. See also 0x26.
Entity Action (0x13)
Client to Server
Sent at least when crouching, leaving a bed, or sprinting. To send action animation to client use 0x28. The client will send this with Action ID = 3 when "Leave Bed" is clicked.
Packet ID | Field Name | Field Type | Example | Notes |
0x13 | EID | int | 55534
|
Player ID |
Action ID | byte | 1
|
The ID of the action, see below. | |
Total Size: | 6 bytes |
Action ID can be one of the following values:
ID | Action |
---|---|
1 | Crouch |
2 | Uncrouch |
3 | Leave bed |
4 | Start sprinting |
5 | Stop sprinting |
Spawn Named Entity (0x14)
Server to Client
The only named entities (at the moment) are players (either real or NPC/Bot). This packet is sent by the server when a player comes into visible range, not when a player joins.
Servers can, however, safely spawn player entities for players not in visible range. The client appears to handle it correctly.
At one point, the Notchian client was not okay with receiving player entity packets, including 0x14, that refer to its own username or EID; and would teleport to the absolute origin of the map and fall through the Void any time it received them. However, in more recent versions, it appears to handle them correctly, by spawning a new entity as directed (though future packets referring to the entity ID may be handled incorrectly).
Packet ID | Field Name | Field Type | Example | Notes |
0x14 | EID | int | 94453
|
Player ID |
Player Name | string | Twdtwd
|
Max length of 16 | |
X | int | 784
|
Player X as Absolute Integer | |
Y | int | 2131
|
Player Y as Absolute Integer | |
Z | int | -752
|
Player Z as Absolute Integer | |
Yaw | byte | 0
|
Player rotation as a packed byte | |
Pitch | byte | 0
|
Player rotation as a packed byte | |
Current Item | short | 0
|
The item the player is currently holding. Note that this should be 0 for "no item", unlike -1 used in other packets. A negative value crashes clients. | |
Metadata | Metadata |
|
The 1.3 client crashes on packets with no metadata, but the server can send any metadata key of 0, 1 or 8 and the client is fine. | |
Total Size: | 22 bytes + length of strings + metadata (at least 1) |
Spawn Dropped Item (0x15)
Server to Client
An 0x15 packet is sent by the server whenever an item on the ground (say a pickaxe thrown on the ground) comes into range of the player. (note: this means range for item vision, not range for pickup!) It used to be sent by the client when an item is dropped from a tile (chest or furnace) or from inventory, but that is now done with the new packets for server-side inventory (see Window click (0x66)).
It is completely acceptable for servers to ignore the EID issued by the client in this packet and instead create a new packet with a server-controlled EID when sending this packet out to clients.
Packet ID | Field Name | Field Type | Example | Notes |
0x15 | EID | int | 157617
|
Unique entity ID |
Slot | slot | The item to be spawned | ||
X | int | 133
|
Item X as Absolute Integer | |
Y | int | 913
|
Item Y as Absolute Integer | |
Z | int | 63552
|
Item Z as Absolute Integer | |
Rotation | byte | 252
|
Item rotation as a packed byte | |
Pitch | byte | 25
|
Item pitch as a packed byte | |
Roll | byte | 12
|
Item roll as a packed byte | |
Total Size: | 20 bytes + slot data |
The "Damage" field inside the slot data structure is also used to store item metadata. For example: you mined birch wood (its id is the same as normal wood) so you must set damage to the metadata of birch wood (2). The same for wool. Id is the same but data is different. For example: you mined blue wool so your damage field should send value 0xB.
Collect Item (0x16)
Server to Client
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 (0x1D does that), and it doesn't add it to your inventory (0x68 does that). The server only checks for items to be picked up after each Player Position and Player Position & Look packet sent by the client.
Packet ID | Field Name | Field Type | Example | Notes |
0x16 | Collected EID | int | 38
|
|
Collector EID | int | 20
|
||
Total Size: | 9 bytes |
Spawn Object/Vehicle (0x17)
Server to Client
Sent by the server when an Object/Vehicle is created. The throwers entity id is now used for fishing floats too.
Packet ID | Field Name | Field Type | Example | Notes |
0x17 | EID | int | 62
|
Entity ID of the Object |
Type | byte | 11
|
The type of object (see Entities#Objects) | |
X | int | 16080
|
The Absolute Integer X Position of the object | |
Y | int | 2299
|
The Absolute Integer Y Position of the object | |
Z | int | 592
|
The Absolute Integer Z Position of the object | |
Object Data | int | 0
|
If this is bigger than 0, the next 3 fields are sent. | |
Speed X | short | 0
|
Not sent if the Object data is 0. The speed of this entity along the X axis. | |
Speed Y | short | 0
|
Not sent if the Object data is 0. The speed of this entity along the Y axis. | |
Speed Z | short | 0
|
Not sent if the Object data is 0. The speed of this entity along the Z axis. | |
Total Size: | 22 or 28 bytes |
Spawn Mob (0x18)
Server to Client
Sent by the server when a Mob Entity is Spawned
Packet ID | Field Name | Field Type | Example | Notes |
0x18 | EID | int | 446
|
Entity ID |
Type | byte | 91
|
The type of mob. See Entities#Mobs | |
X | int | 13366
|
The Absolute Integer X Position of the object | |
Y | int | 2176
|
The Absolute Integer Y Position of the object | |
Z | int | 1680
|
The Absolute Integer Z Position of the object | |
Yaw | byte | -27
|
The yaw in steps of 2p/256 | |
Pitch | byte | 0
|
The pitch in steps of 2p/256 | |
Head Yaw | byte | Head yaw in steps of 2p/256 | ||
Velocity Z | short | 0
|
||
Velocity X | short | 0
|
||
Velocity Y | short | 0
|
||
Metadata | Metadata | 127
|
Varies by mob, see Entities | |
Total Size: | 27 bytes + Metadata (at least 1) |
Spawn Painting (0x19)
Server to Client
This packet shows location, name, and type of painting.
Packet ID | Field Name | Field Type | Example | Notes |
0x19 | Entity ID | int | 0x00000326
|
Unique entity ID |
Title | string | Creepers
|
Name of the painting; max length 13 (length of "SkullAndRoses") | |
X | int | 50
|
Center X coordinate | |
Y | int | 66
|
Center Y coordinate | |
Z | int | -50
|
Center Z coordinate | |
Direction | int | 0
|
Direction the painting faces (0 -z, 1 -x, 2 +z, 3 +x) | |
Total Size: | 23 bytes + length of string |
Calculating the center of an image: given a (width x height) grid of cells, with (0, 0) being the top left corner, the center is (max(0, width / 2 - 1), height / 2). E.g.
2x1 (1, 0) 4x4 (1, 2)
Spawn Experience Orb (0x1A)
Server to Client
Spawns one or more experience orbs. Coordinates are in absolute units.
Packet ID | Field Name | Field Type | Example | Notes |
0x1A | Entity ID | int | 105668 | |
x | int | -1143 | ||
y | int | 1952 | ||
z | int | 1166 | ||
count | short | 7 | ||
Total Size: | 19 bytes |
Entity Velocity (0x1C)
Server to Client
This packet is new to version 4 of the protocol, and is believed to be Entity Velocity/Motion.
Velocity is believed to be in units of 1/32000 of a block per server tick (200ms); for example, -1343 would move (-1343 / 32000) = -0.04196875 blocks per tick (or -0.20984375 blocks per second).
Each axis' velocity is capped between -0.9 and 0.9 blocks per tick (packet values -28800 to 28800).
(This packet data values are not fully verified)
Packet ID | Field Name | Field Type | Example | Notes |
0x1C | Entity ID | int | 1805
|
The entity ID |
Velocity X | short | -1343
|
Velocity on the X axis | |
Velocity Y | short | 0
|
Velocity on the Y axis | |
Velocity Z | short | 0
|
Velocity on the Z axis | |
Total Size: | 11 bytes |
Destroy Entity (0x1D)
Server to Client
Sent by the server when an list of Entities is to be destroyed on the client.
Packet ID | Field Name | Field Type | Example | Notes |
0x1D | Entity Count | byte | 3
|
The amount of entities which should be destroyed |
Entity IDs | array of int | 452, 546, 123
|
The list of entity ids which should be destroyed | |
Total Size: | 2 + (entity count * 4) bytes |
Entity (0x1E)
Server to Client
Most entity-related packets are subclasses of this packet. When sent from the server to the client, it may initialize the entry.
For player entities, either this packet or any move/look packet is sent every game tick. So the meaning of this packet is basically that the entity did not move/look since the last such packet.
Packet ID | Field Name | Field Type | Example | Notes |
0x1E | EID | int | 446
|
Entity ID |
Total Size: | 5 bytes |
Entity Relative Move (0x1F)
Server to Client
This packet is sent by the server when an entity moves less then 4 blocks; if an entity moves more than 4 blocks Entity Teleport should be sent instead.
This packet allows at most four blocks movement in any direction, because byte range is from -128 to 127. Movement is an offset of Absolute Int; to convert relative move to block coordinate offset, divide by 32.
Packet ID | Field Name | Field Type | Example | Notes |
0x1F | EID | int | 459
|
Entity ID |
dX | byte | 1
|
X axis Relative movement as an Absolute Integer | |
dY | byte | -7
|
Y axis Relative movement as an Absolute Integer | |
dZ | byte | 5
|
Z axis Relative movement as an Absolute Integer | |
Total Size: | 8 bytes |
Entity Look (0x20)
Server to Client
This packet is sent by the server when an entity rotates. Example: "Yaw" field 64 means a 90 degree turn.
Packet ID | Field Name | Field Type | Example | Notes |
0x20 | EID | int | 459
|
Entity ID |
Yaw | byte | 126
|
The X Axis rotation as a fraction of 360 | |
Pitch | byte | 0
|
The Y Axis rotation as a fraction of 360 | |
Total Size: | 7 bytes |
Entity Look and Relative Move (0x21)
Server to Client
This packet is sent by the server when an entity rotates and moves. Since a byte range is limited from -128 to 127, and movement is offset of Absolute Int, this packet allows at most four blocks movement in any direction. (-128/32 == -4)
Packet ID | Field Name | Field Type | Example | Notes |
0x21 | EID | int | 459
|
Entity ID |
dX | byte | 1
|
X axis Relative movement as an Absolute Integer | |
dY | byte | -7
|
Y axis Relative movement as an Absolute Integer | |
dZ | byte | 5
|
Z axis Relative movement as an Absolute Integer | |
Yaw | byte | 126
|
The X Axis rotation as a fraction of 360 | |
Pitch | byte | 0
|
The Y Axis rotation as a fraction of 360 | |
Total Size: | 10 bytes |
Entity Teleport (0x22)
Server to Client
This packet is sent by the server when an entity moves more than 4 blocks.
Packet ID | Field Name | Field Type | Example | Notes |
0x22 | EID | int | 459
|
Entity ID |
X | int | 14162
|
X axis position as an Absolute Integer | |
Y | int | 2176
|
Y axis position as an Absolute Integer | |
Z | int | 1111
|
Z axis position as an Absolute Integer | |
Yaw | byte | 126
|
The X Axis rotation as a fraction of 360 | |
Pitch | byte | 0
|
The Y Axis rotation as a fraction of 360 | |
Total Size: | 19 bytes |
Entity Head Look (0x23)
Server to Client
Changes the direction an entity's head is facing.
Packet ID | Field Name | Field Type | Example | Notes |
0x23 | Entity ID | int | ||
Head Yaw | byte | Head yaw in steps of 2p/256 | ||
Total Size: | 6 bytes |
Entity Status (0x26)
Server to Client
Packet ID | Field Name | Field Type | Example | Notes |
0x26 | Entity ID | Int | 34353 | |
Entity Status | Byte | 0x03 | See below | |
Total Size: | 6 bytes |
Entity Status | Meaning |
---|---|
2 | Entity hurt |
3 | Entity dead |
6 | Wolf taming |
7 | Wolf tamed |
8 | Wolf shaking water off itself |
9 | (of self) Eating accepted by server |
10 | Sheep eating grass |
Attach Entity (0x27)
Server to Client
This packet is new to version 4 of the protocol, and is believed to be Attach Entity.
This packet is sent when a player has been attached to an entity (e.g. Minecart)
(This packet data values are not fully verified)
Packet ID | Field Name | Field Type | Example | Notes |
0x27 | Entity ID | int | 1298
|
The player entity ID being attached |
Vehicle ID | int | 1805
|
The vehicle entity ID attached to (-1 for unattaching) | |
Total Size: | 9 bytes |
Entity Metadata (0x28)
Server to Client
Packet ID | Field Name | Field Type | Example | Notes |
0x28 | Entity ID | int | 0x00000326
|
Unique entity ID to update. |
Entity Metadata | Metadata | 0x00 0x01 0x7F
|
Metadata varies by entity. See Entities | |
Total Size: | 5 bytes + Metadata |
Entity Effect (0x29)
Server to Client
Packet ID | Field Name | Field Type | Example | Notes |
0x29 | Entity ID | int | 14
|
Entity ID of a player |
Effect ID | byte | 17
|
See here | |
Amplifier | byte | 0
|
||
Duration | short | 64
|
||
Total Size: | 9 bytes |
Remove Entity Effect (0x2A)
Server to Client
Packet ID | Field Name | Field Type | Example | Notes |
0x2a | Entity ID | int | Entity ID of a player | |
Effect ID | byte | 17
|
See table above | |
Total Size: | 6 bytes |
Set Experience (0x2B)
Server to Client
Sent by the server when the client should change experience levels.
Packet ID | Field Name | Field Type | Example | Notes |
0x2B | Experience bar | float | 0.5960060358047485
|
Used for drawing the experience bar - value is between 0 and 1. |
Level | short | 8
|
||
Total experience | short | 130
|
||
Total Size: | 9 bytes |
Chunk Data (0x33)
Server to Client
See also: Map Format
Chunks are sent a column at a time, with some sections optionally missing from each packet (those consisting only of air).
Packet ID | Field Name | Field Type | Example | Notes |
0x33 | X | int | Chunk X Coordinate (*16 to get true X) | |
Z | int | Chunk Z Coordinate (*16 to get true Z) | ||
Ground-up continuous | boolean | This is True if the packet represents all sections in this vertical column, where the primary bit map specifies exactly which sections are included, and which are air. | ||
Primary bit map | unsigned short | 15 | Bitmask with 1 for every 16x16x16 section which data follows in the compressed data. | |
Add bit map | unsigned short | 0 | Same as above, but this is used exclusively for the 'add' portion of the payload | |
Compressed size | int | Size of compressed chunk data. | ||
Compressed data | unsigned byte array | …
|
The chunk data is compressed using ZLib Deflate function. | |
Total Size: | 18 bytes + Compressed chunk size |
The payload is a set of 16x16x16 sections, sharing the same X and Z coordinates. What is and isn't sent is provided by the two bitmask fields. The least significant bit is '1' if the section spanning from Y=0 to Y=15 is not completely air, and so forth. For block IDs, metadata, and lighting, the primary bitmask is used. A secondary bitmask is used for 'add' data, which is Mojang's means of provided Block IDs past 256. In vanilla minecraft, you can expect this to always be zero. The sections included in this packet progress from bottom to top, where Y=0 is the bottom.
The data is compressed using the deflate() function in zlib. After uncompressing, the data consists of five (or six) sequential sections, in order:
- Block type array (1 byte per block, 4096 bytes per section)
- Block metadata array (half byte per block, 2048 bytes per section)
- Block light array (half byte per block, 2048 bytes per section)
- Sky light array (half byte per block, 2048 bytes per section)
- Add array (half byte per block, 2048 bytes per section, uses second bitmask)
- Biome array (1 byte per XZ coordinate, 256 bytes total, only sent if 'ground up continuous' is true)
Each section is the concatenated data of all included sections (i.e. the block type array contains the block types of all included sections).
In each section except biome data, your decoder loop should look something like this:
//Loop over 16x16x16 sections in the 16x256x16 chunk
for (i=0;i<16;i++) {
//If the bitmask indicates this chunk has been sent...
if (bitmask & 1 << i) {
//Read data...
cubic_chunk_data = io.read(4096); //2048 for the other arrays, where you'll need to split the data
for(int j=0; j<len(cubic_chunk_data); j++) {
//Retrieve x,y,z and data from each element in cubic_chunk_array
//Byte arrays
x = chunk_x*16 + j & 0x0F;
y = i*16 + j >> 8;
z = chunk_z*16 + (j & 0xF0) >> 4;
data = cubic_chunk_data[j]
//Nibble arrays
data1 = cubic_chunk_data[j] & 0x0F;
data2 = cubic_chunk_data[j] >> 4;
k = 2*j;
x1 = chunk_x*16 + k & 0x0F;
y1 = i*16 + k >> 8;
z1 = chunk_z*16 + (k & 0xF0) >> 4;
k++;
x2 = chunk_x*16 + k & 0x0F;
y2 = i*16 + k >> 8;
z2 = chunk_z*16 + (k & 0xF0) >> 4;
}
}
}
Each biome byte can have the values from 0 to 22, higher will cause the client to crash.
The 'add' array uses the second bitmask. Block IDs are presumed to be block_id | add << 8
Here's an example of how this packet could be encoded.
Multi Block Change (0x34)
Server to Client
Packet ID | Field Name | Field Type | Example | Notes |
0x34 | Chunk X | int | -9
|
Chunk X Coordinate |
Chunk Z | int | 12
|
Chunk Z Coordinate | |
Record count | short | The number of blocks affected | ||
Data size | int | The total size of the data, in bytes. Should always be 4*record count - please confirm. | ||
Data | …
|
Coordinates, type, and metadata of blocks to change (see below table). | ||
Total Size: | 15 bytes + Arrays |
Each record is four bytes.
Bit mask | Width | Meaning |
00 00 00 0F | 4 bits | Block metadata |
00 00 FF F0 | 12 bits | Block ID |
00 FF 00 00 | 8 bits | Y co-ordinate |
0F 00 00 00 | 4 bits | Z co-ordinate, relative to chunk |
F0 00 00 00 | 4 bits | X co-ordinate, relative to chunk |
Block Change (0x35)
Server to Client
Packet ID | Field Name | Field Type | Example | Notes |
0x35 | X | int | 502
|
Block X Coordinate |
Y | byte | 71
|
Block Y Coordinate | |
Z | int | 18
|
Block Z Coordinate | |
Block Type | short | 78
|
The new block type for the block | |
Block Metadata | byte | 0
|
The new Metadata for the block | |
Total Size: | 13 bytes |
Block Action (0x36)
Server to Client
This packet is used for a number of things:
- Chests opening and closing
- Pistons pushing and pulling
- Note blocks playing
Packet ID | Field Name | Field Type | Example | Notes |
0x36 | X | int | 502
|
Block X Coordinate |
Y | short | 71
|
Block Y Coordinate | |
Z | int | 18
|
Block Z Coordinate | |
Byte 1 | byte | 3
|
Varies depending on block - see below | |
Byte 2 | byte | 17
|
Varies depending on block - see below | |
Block ID | short | 29
|
The block id this action is set for | |
Total Size: | 15 bytes |
See Also: Block Actions
Block Break Animation (0x37)
Server to Client
Packet ID | Field Name | Field Type | Example | Notes |
0x37 | EID? | int | Entity breaking the block? | |
X | int | Block position | ||
Y | int | |||
Z | int | |||
Destroy Stage | byte | 1 | How far destroyed this block is. | |
Total Size: | 18 bytes |
Map Chunk Bulk (0x38)
Server to Client
To reduce the number of bytes this packet is used to send chunks together for better compression results. The packet contains up to 100 chunks (later this might be reduced to 50).
The data part is a zlib compressed byte array containing the chunk data. The meta data part specifies which chunks in which order the data part exists of.
To split this packet into chunks you need to uncompress the data array. Then you can iterate through the data part. Each part is 10240 * n + 256 bytes. n is the number of sections in the current chunk (this is the number of flags set in the primary bitmap). 10240 is the amount of bytes for each chunk without add bitmap, 256 bytes are used for biomes. The second short in the meta data part is not yet in use. It could specify if the chunk uses the add bitmap part, because it has very high block ids, but not in the current snapshot.
Packet ID | Field Name | Field Type | Example | Notes |
0x38 | Chunk Count | short | The number of chunks in this packet | |
Chunk data length | int | the size of the data field | ||
Data | byte array | Compressed chunk data | ||
meta information | chunk bulk meta information | Chunk count times the Meta information structure (See notes for details) | ||
Total Size: | 7 + (Chunk data size) + 12 * (Chunk Count) bytes |
Chunk Bulk Meta Information Structure
Field Name | Field Type | Example | Notes |
Chunk X | int | 10 | The X coordinate of the specific chunk |
Chunk Z | int | 10 | The Z coordinate of the specific chunk |
Primary bitmap | short | 15 | A bitmap which specifies which sections are not empty in this chunk |
Add bitmap? | short | 0 | A bitmap which specifies which sections need add information because of very high block ids. not yet used. needs verification |
Total Size: | 12 bytes |
Explosion (0x3C)
Server to Client
Sent when an explosion occurs (creepers, TNT, and ghast fireballs).
Packet ID | Field Name | Field Type | Example | Notes |
0x3C | X | double | ||
Y | double | |||
Z | double | |||
Radius | float | 3.0 | Currently unused in the client | |
Record count | int | This is the count, not the size. The size is 3 times this value. | ||
Records | (byte, byte, byte) × count | Each record is 3 signed bytes long, each bytes are the XYZ (respectively) 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 | ||
Total Size: | 45 bytes + 3*(Record count) bytes |
Each block in Records is set to air. Coordinates for each axis in record is int(X) + record.x
Sound Or Particle Effect (0x3D)
Server to Client
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 1013 (mob.wither.spawn), and is ignored for any other value by the client.
Packet ID | Field Name | Field Type | Example | Notes |
0x3D | Effect ID | int | 1003 | The ID of the effect, see below. |
X | int | The X location of the effect. | ||
Y | byte | The Y location of the effect. | ||
Z | int | The Z location of the effect. | ||
Data | int | 0 | Extra data for certain effects, see below. | |
No Volume Decrease | boolean | false | See above | |
Total Size: | 19 bytes |
Effects
Sound:
- 1000:
random.click
- 1001:
random.click
- 1002:
random.bow
- 1003:
random.door_open
orrandom.door_close
(50/50 chance) - 1004:
random.fizz
- 1005: Play a music disc. Data: Record ID
- (1006 not assigned)
- 1007:
mob.ghast.charge
- 1008:
mob.ghast.fireball
- (1009 not assigned)
- 1010:
mob.zombie.wood
- 1011:
mob.zombie.metal
- 1012:
mob.zombie.woodbreak
- 1013:
mob.wither.spawn
Particle:
- 2000: Spawns 10 smoke particles, e.g. from a fire. Data: direction, see below
- 2001: Block break. Data: Block ID
- 2002: Splash potion. Particle effect + glass break sound. Data: Potion ID
- 2003: Eye of ender. Actual client effect to be determined.
- 2004: Mob spawn particle effect: smoke + flames
Smoke directions:
ID | Direction |
0 | South - East |
1 | South |
2 | South - West |
3 | East |
4 | (Up or middle ?) |
5 | West |
6 | North - East |
7 | North |
8 | North - West |
Named Sound Effect (0x3E)
Server to client
Used to play a sound effect on the client.
All known sound effect names can be seen here.
Packet ID | Field Name | Field Type | Example | Notes |
0x3E | Sound name | string | step.grass | 250 |
Effect position X | int | 250 | effect X multiplied by 8 | |
Effect position Y | int | 250 | effect Y multiplied by 8 | |
Effect position Z | int | 250 | effect Z multiplied by 8 | |
Volume | float | 9 | 1 is 100%, can be more | |
Pitch | byte | 1 | 63 is 100%, can be more | |
Total Size: | 20 bytes + length of string |
Change Game State (0x46)
Server to Client
This packet appeared with protocol version 10. Currently, it appears when a bed can't be used as a spawn point and when the rain state changes. it could have additional uses in the future.
The class has an array of strings linked to reason codes 0, 1, 2, and 3 but only the codes for 1 and 2 are null.
Packet ID | Field Name | Field Type | Example | Notes |
0x46 | Reason | byte | 0 | |
Game mode | byte | 0 | Used only when reason = 3. 0 is survival, 1 is creative. | |
Total Size: | 3 bytes |
Reason codes
Code | Effect | Text |
---|---|---|
0 | Invalid Bed | "tile.bed.notValid" |
1 | Begin raining | null |
2 | End raining | null |
3 | Change game mode | gameMode.changed |
4 | Enter credits |
Global Entity (0x47)
Server to Client
With this packet, the server notifies the client of thunderbolts striking within a 512 block radius around the player. The coordinates specify where exactly the thunderbolt strikes.
Packet ID | Field Name | Field Type | Example | Notes |
0x47 | Entity ID | int | 4 | The entity ID of the thunderbolt |
ID | byte | 1 | The global entity, currently always 1 for thunderbolt. | |
X | int | 133 | Thunderbolt X as Absolute Integer | |
Y | int | 913 | Thunderbolt Y as Absolute Integer | |
Z | int | 63552 | Thunderbolt Z as Absolute Integer | |
Total Size: | 18 bytes |
Open Window (0x64)
Server to Client
This is sent to the client when it should open an inventory, such as a chest, workbench, or furnace. This message is not sent anywhere for clients opening their own inventory.
Packet ID | Field Name | Field Type | Example | Notes |
0x64 | Window id | byte | 123 | A unique id number for the window to be displayed. Notchian server implementation is a counter, starting at 1. |
Inventory Type | byte | 2 | The window type to use for display. Check below | |
Window title | string | Chest
|
The title of the window. | |
Number of Slots | byte | 3 | Number of slots in the window (excluding the number of slots in the player inventory). | |
Total Size: | 6 bytes + length of string |
The window titles sent by the Notchian server are "Chest", "Large chest", "Crafting", "Furnace", and "Trap". Notchian clients force window titles for some windows, like dispensers and furnaces, but other titles are customizable. However, the window title sent by the server is always used for chests. See inventory windows for further information.
Close Window (0x65)
Two-Way
This packet is sent by the client when closing a window. 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.
Note, notchian clients send a close window message with window id 0 to close their inventory even though there is never an Open Window message for inventory.
Packet ID | Field Name | Field Type | Example | Notes |
0x65 | Window id | byte | 0 | This is the id of the window that was closed. 0 for inventory. |
Total Size: | 2 bytes |
Click Window (0x66)
Client to Server
This packet is sent by the player when it clicks on a slot in a window.
Packet ID | Field Name | Field Type | Example | Notes |
0x66 | Window id | byte | 0
|
The id of the window which was clicked. 0 for player inventory. |
Slot | short | 36
|
The clicked slot. See below. | |
Mouse button | byte | 1
|
0: left click, 1: right click, 3: middle click ("shift" is set to 2 in this case) | |
Action number | short | 12
|
A unique number for the action, used for transaction handling (See the Transaction packet). | |
Shift | boolean | 0
|
This is true if the user was holding keyboard shift when they clicked. | |
Clicked item | slot | |||
Total Size: | 8 bytes + slot data |
See inventory windows for further information about how slots are indexed.
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 Action number is actually a counter, starting at 1. This number is used by the server as a transaction ID to send back a Transaction packet.
Set Slot (0x67)
Server to Client
Sent by the server when an item in a slot (in a window) is added/removed.
Packet ID | Field Name | Field Type | Example | Notes |
0x67 | Window id | byte | 0
|
The window which is being updated. 0 for player inventory. Note that all known window types include the player inventory. This packet will only be sent for the currently opened window while the player is performing actions, even if it affects the player inventory. After the window is closed, a number of these packets are sent to update the player's inventory window (0). |
Slot | short | 36
|
The slot that should be updated | |
Slot data | slot | |||
Total Size: | 4 bytes + slot data |
Note that if window ID and slot are both -1, it means the item currently attached to the cursor.
See inventory windows for further information about how slots are indexed.
Slots: [1]
Set Window Items (0x68)
Server to Client
Sent by the server when an item in a slot (in a window) is added/removed. This includes the main inventory, equipped armour and crafting slots.
Packet ID | Field Name | Field Type | Example | Notes |
0x68 | Window id | byte | 1
|
The id of window which items are being sent for. 0 for player inventory. |
Count | short | 4
|
The number of slots (see below) | |
Slot data | array of slots | |||
Total Size: | 4 bytes + size of slot data array |
See inventory windows for further information about how slots are indexed.
Update Window Property (0x69)
Server to Client
Packet ID | Field Name | Field Type | Example | Notes |
0x69 | Window id | byte | 2 | The id of the window. |
Property | short | 1 | Which property should be updated. | |
Value | short | 650 | The new value for the property. | |
Total Size: | 6 bytes |
Furnace
Properties:
- 0: Progress arrow
- 1: Fire icon (fuel)
Values:
- 0-180 for progress arrow
- 0-250 for fuel indicator
Ranges are presumably in in-game ticks
Enchantment Table
Properties: 0, 1 or 2 depending on the "enchantment slot" being given.
Values: The enchantment's level.
Confirm Transaction (0x6A)
Two-Way
A packet from the server indicating whether a request from the client was accepted, or whether there was a conflict (due to lag). This packet is also sent from the client to the server in response to a server transaction rejection packet.
Packet ID | Field Name | Field Type | Example | Notes |
0x6A | Window id | byte | 0 | The id of the window that the action occurred in. |
Action number | short | 12 | Every action that is to be accepted has a unique number. This field corresponds to that number. | |
Accepted? | boolean | true | Whether the action was accepted. | |
Total Size: | 5 bytes |
Creative Inventory Action (0x6B)
Two-Way
While the user is in the standard inventory (i.e., not a crafting bench) on a creative-mode server then the server will send this packet:
- If an item is dropped into the quick bar
- If an item is picked up from the quick bar (item id is -1)
Packet ID | Field Name | Field Type | Example | Notes |
0x6B | Slot | short | 36 | Inventory slot |
Clicked item | slot | |||
Total Size: | 3 bytes + slot data |
Enchant Item (0x6C)
Client to Server
Packet ID | Field Name | Field Type | Example | Notes |
0x6C | Window ID | byte | 1 | The ID sent by Open Window |
Enchantment | byte | 0 | The position of the enchantment on the enchantment table window, starting with 0 as the topmost one. | |
Total Size: | 3 bytes |
Update Sign (0x82)
Two-Way
Packet ID | Field Name | Field Type | Example | Notes |
0x82 | X | int | 128 | Block X Coordinate |
Y | short | 0 | Block Y Coordinate | |
Z | int | -128 | Block Z Coordinate | |
Text1 | string | First line
|
First line of text in the sign | |
Text2 | string | Second line
|
Second line of text in the sign | |
Text3 | string | Third line
|
Third line of text in the sign | |
Text4 | string | Fourth line
|
Fourth line of text in the sign | |
Total Size: | 11 bytes + 4 strings |
This message is sent from the server to the client whenever a sign is discovered or created. This message is sent from the client to the server when the "Done" button is pushed after placing a sign. This message is NOT sent when a sign is destroyed or unloaded.
Item Data (0x83)
Server to Client
Sent to specify complex data on an item; currently used only for maps.
Packet ID | Field Name | Field Type | Example | Notes |
0x83 | Item Type | short | 358
|
Type of item being modified |
Item ID | short | 0
|
The ID (damage value) of the item being modified | |
Text length | unsigned byte | 35
|
Length of following byte array | |
Text | byte array | {0,0,0,20,20,20,20,20} | ASCII text. | |
Total Size: | 6 bytes + Text length |
Maps If the first byte of the text is 0, the next two bytes are X start and Y start and the rest of the bytes are the colors in that column.
If the first byte of the text is 1, the rest of the bytes are in groups of three: (data, x, y). The lower half of the data is the type (always 0 under vanilla) and the upper half is the direction.
Update Tile Entity (0x84)
Server to Client
Essentially a block update on a tile entity.
Packet ID | Field Name | Field Type | Example | Notes |
0x84 | X | int | ||
Y | short | |||
Z | int | |||
Action | byte | The type of update to perform | ||
Data length | Short | Varies | ||
NBT Data | Byte Array - Present if data length > 0 | Compressed with gzip. Varies | ||
Total Size: | 12 + itemstack bytes |
Actions
- 1: Set mob displayed inside a mob spawner. Custom 1 contains the mob type
Increment Statistic (0xC8)
Server to Client
Packet ID | Field Name | Field Type | Example | Notes |
0xC8 | Statistic ID | int | 1003 | The ID of the statistic. See List of statistics. |
Amount | byte | 1 | The amount to increment the statistic. | |
Total Size: | 6 bytes |
Player List Item (0xC9)
Server to Client
Sent by the notchian server to update the user list (<tab> in the client). The server sends one packet per user per tick, amounting to 20 packets/s for 1 online user, 40 for 2, and so forth.
Packet ID | Field Name | Field Type | Example | Notes |
0xC9 | Player name | string | barneygale | Supports chat colouring, limited to 16 characters. |
Online | boolean | true | If false, the client will remove the user from the list. | |
Ping | short | 193 | Ping, presumably in ms. | |
Total Size: | 6 bytes + length of string |
Player Abilities (0xCA)
Two-Way
The latter 2 bytes are used to indicate the walking and flying sppeds respectively, while the first byte is used to determine the value of 4 booleans.
These booleans are whether damage is disabled (god mode), whether the player is flying, whether the player can fly, and whether the player is in creative mode.
To get the values of these booleans, simply AND (&) the byte with 1,2,4 and 8 respectively, to get the 0 or 1 bitwise value. To set them OR (|) them with their repspective masks. The vanilla client sends this packet when the player starts/stops flying with the second parameter changed accordingly. All other parameters are ignored by the vanilla server.
Packet ID | Field Name | Field Type | Example | Notes |
0xCA | Flags | byte | 5 | |
Flying speed | byte | 12 | ||
Walking speed | byte | 25 | ||
Total Size: | 4 bytes |
Tab-complete (0xCB)
Two-way
Sent C->S when the user presses [tab] while writing text. The payload contains all text behind the cursor.
The server responds with an auto-completion 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.
In the event of more than one possible completion, the server responds with the options packed into the single string field, separated by a null character. Note that as strings are UTF-16, this is two bytes wide.
Packet ID | Field Name | Field Type | Example | Notes |
0xCB | Text | string | ||
Total Size: | 3 bytes + length of string |
Client Settings (0xCC)
Client to server
Sent when the player connects, or when settings are changed.
Packet ID | Field Name | Field Type | Example | Notes |
0xCC | Locale | string | en_GB | |
View distance | byte | 0 | 0-3 for 'far', 'normal', 'short', 'tiny'. | |
Chat flags | byte | 8 | Chat settings. See notes below. | |
Difficulty | byte | 0 | Client-side difficulty from options.txt | |
Show Cape | boolean | true | Client-side "show cape" option | |
Total Size: | 7 bytes + length of string |
Chat flags has several values packed into one byte.
Chat Enabled: Bits 0-1. 00: Enabled. 01: Commands only. 10: Hidden.
Colors Enabled: Bit 3. 0: Disabled. 1: Enabled.
Client Statuses (0xCD)
Client to server
Sent when the client is ready to complete login and when the client is ready to respawn after death.
Packet ID | Field Name | Field Type | Example | Notes | |
0xCD | Payload | byte | 0 | Bit field. 0: Initial spawn, 1: Respawn after death | |
Total Size: | 2 bytes |
Plugin Message (0xFA)
Two-Way
Mods and plugins can use this to send their data. As of 1.3, Minecraft itself uses a number of plugin channels. These internal channels are prefixed with MC|
.
Packet ID | Field Name | Field Type | Example | Notes |
0xFA | Channel | string | MyMod:testchannel | Name of the "channel" used to send the data. |
length | short | Length of the following byte array | ||
data | byte array | Any data. | ||
Total Size: | 5 bytes + length of string + length of byte array |
More documentation on this: http://dinnerbone.com/blog/2012/01/13/minecraft-plugin-channels-messaging/
Encryption Key Response (0xFC)
Two-Way
See Protocol Encryption for information on this packet. Bypassing the encryption is possible, authentication for the player name is still needed if the server is in online mode, but instead of sending this packet, you send Client Statuses instead.
Packet ID | Field Name | Field Type | Example | Notes |
0xFC | Shared secret length | short | ||
Shared secret | byte array | |||
Verify token length | short | |||
Verify token response | byte array | |||
Total Size: | 5 bytes + length of shared secret + length of token |
Encryption Key Request (0xFD)
Server to client
See Protocol Encryption for information on this packet.
Packet ID | Field Name | Field Type | Example | Notes |
0xFD | Server id | string | ||
Public key length | short | |||
Public key | byte array | |||
Verify token length | short | |||
Verify token | byte array | |||
Total Size: | 7 bytes + length of string + length of key + length of token |
Server List Ping (0xFE)
Client to Server
This packet is used by the multiplayer menu to retrieve MOTD, version, and player counts. For more info see Server List Ping
Packet ID | Field Name | Field Type | Example | Notes |
0xFE | Magic | byte | 1
|
always 1
|
Total Size: | 2 bytes |
Disconnect/Kick (0xFF)
Two-Way
Sent by the server before it disconnects a client, or by the client before it disconnects from the server. The receiver of this packet assumes that the sender has already closed the connection by the time the packet arrives.
Due to race conditions in the client, a local server may need to pause for a short period after sending this packet before closing the connection. An alternative is simply not to close the connection, and wait for the client to do so on receipt of this packet.
Packet ID | Field Name | Field Type | Example | Notes |
0xFF | Reason | string | The server is full!
|
Displayed to the client when the connection terminates |
Total Size: | 3 bytes + length of strings |