Pre-release protocol

This page documents the changes from the last stable Minecraft release (currently 1.12.2, protocol 340) to the current pre-release (currently 1.13-pre8, protocol 390). Note that this page contains bleeding-edge information that may not be completely or correctly documented.

One who wishes to commandeer the merging of this into Protocol when an update is made must be sure to respect any changes that may have occurred to the respective packets there.

Contents

Data types

Other definitions

Global palette

A table/dictionary/palette mapping nonnegative integers to block states. The block state IDs can be constructed from this table by multiplying what the Minecraft Wiki calls “block IDs” by 16 and adding the metadata/damage value (or in most programming languages block_id << 4 | metadata). Block state IDs are created in a linear fashion based off of order of assignment. One block state ID allocated for each unique block state for a block; if a block has multiple properties then the number of allocated states is the product of the number of values for each property. 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 -cp minecraft_server.18w22c.jar net.minecraft.data.Main --reports (use --help for a list of other options). One can parse the generated blocks.json to convert known block states to and from ids.

Packets

ID	Packet name	Documentation
Handshaking serverbound
0x00	Handshake	Current	Pre
Play clientbound
0x04	Spawn Painting	Current	Pre
0x07	Statistics	Current	Pre
0x09	Update Block Entity	Current	Pre
0x0B	Block Change	Current	Pre
0x0F 0x0E	Chat Message (clientbound)	Current	(unchanged)
0x10 0x0F	Multi Block Change	Current	Pre
0x0E 0x10	Tab-Complete (clientbound)	Current	Pre
0x11	Declare Commands		Pre
0x11 0x12	Confirm Transaction (clientbound)	Current	(unchanged)
0x12 0x13	Close Window (clientbound)	Current	(unchanged)
0x13 0x14	Open Window	Current	(unchanged)
0x14 0x15	Window Items	Current	(unchanged)
0x15 0x16	Window Property	Current	(unchanged)
0x16 0x17	Set Slot	Current	(unchanged)
0x17 0x18	Set Cooldown	Current	(unchanged)
0x18 0x19	Plugin Message (clientbound)	Current	Pre
0x19 0x1A	Named Sound Effect	Current	Pre
0x1A 0x1B	Disconnect (play)	Current	(unchanged)
0x1B 0x1C	Entity Status	Current	(unchanged)
0x1D	NBT Query Response		Pre
0x1C 0x1E	Explosion	Current	(unchanged)
0x1D 0x1F	Unload Chunk	Current	(unchanged)
0x1E 0x20	Change Game State	Current	(unchanged)
0x1F 0x21	Keep Alive (clientbound)	Current	(unchanged)
0x20 0x22	Chunk Data	Current	Pre
0x21 0x23	Effect	Current	(unchanged)
0x22 0x24	Spawn Particle	Current	Pre
0x23 0x25	Join Game	Current	(unchanged)
0x24 0x26	Map	Current	Pre
0x25 0x27	Entity	Current	(unchanged)
0x26 0x28	Entity Relative Move	Current	(unchanged)
0x27 0x29	Entity Look And Relative Move	Current	(unchanged)
0x28 0x2A	Entity Look	Current	(unchanged)
0x29 0x2B	Vehicle Move (clientbound)	Current	(unchanged)
0x2A 0x2C	Open Sign Editor	Current	(unchanged)
0x2B 0x2D	Craft Recipe Response	Current	Pre
0x2C 0x2E	Player Abilities (clientbound)	Current	(unchanged)
0x2D 0x2F	Combat Event	Current	(unchanged)
0x2E 0x30	Player List Item	Current	(unchanged)
0x31	Face Player		Pre
0x2F 0x32	Player Position And Look (clientbound)	Current	(unchanged)
0x30 0x33	Use Bed	Current	(unchanged)
0x31 0x34	Unlock Recipes	Current	Pre
0x32 0x35	Destroy Entities	Current	(unchanged)
0x33 0x36	Remove Entity Effect	Current	(unchanged)
0x34 0x37	Resource Pack Send	Current	(unchanged)
0x35 0x38	Respawn	Current	(unchanged)
0x36 0x39	Entity Head Look	Current	(unchanged)
0x37 0x3A	Select Advancement Tab	Current	(unchanged)
0x38 0x3B	World Border	Current	(unchanged)
0x39 0x3C	Camera	Current	(unchanged)
0x3A 0x3D	Held Item Change (clientbound)	Current	(unchanged)
0x3B 0x3E	Display Scoreboard	Current	(unchanged)
0x3C 0x3F	Entity Metadata	Current	(unchanged)
0x3D 0x40	Attach Entity	Current	(unchanged)
0x3E 0x41	Entity Velocity	Current	(unchanged)
0x3F 0x42	Entity Equipment	Current	(unchanged)
0x40 0x43	Set Experience	Current	(unchanged)
0x41 0x44	Update Health	Current	(unchanged)
0x42 0x45	Scoreboard Objective	Current	Pre
0x43 0x46	Set Passengers	Current	(unchanged)
0x44 0x47	Teams	Current	Pre
0x45 0x48	Update Score	Current	(unchanged)
0x46 0x49	Spawn Position	Current	(unchanged)
0x47 0x4A	Time Update	Current	(unchanged)
0x48 0x4B	Title	Current	(unchanged)
0x4C	Stop Sound		Pre
0x49 0x4D	Sound Effect	Current	(unchanged)
0x4A 0x4E	Player List Header And Footer	Current	(unchanged)
0x4B 0x4F	Collect Item	Current	(unchanged)
0x4C 0x50	Entity Teleport	Current	(unchanged)
0x4D 0x51	Advancements	Current	(unchanged)
0x4E 0x52	Entity Properties	Current	(unchanged)
0x4F 0x53	Entity Effect	Current	(unchanged)
0x54	Declare Recipes		Pre
0x55	Tags		Pre
Play serverbound
0x01	Query Block NBT		Pre
0x01 0x05	Tab-Complete (serverbound)	Current	Pre
0x05 0x06	Confirm Transaction (serverbound)	Current	(unchanged)
0x06 0x07	Enchant Item	Current	(unchanged)
0x07 0x08	Click Window	Current	(unchanged)
0x08 0x09	Close Window (serverbound)	Current	(unchanged)
0x09 0x0A	Plugin message (serverbound)	Current	Pre
0x0B	Edit Book		Pre
0x0C	Query Entity NBT		Pre
0x0A 0x0D	Use Entity	Current	(unchanged)
0x0B 0x0E	Keep Alive (serverbound)	Current	(unchanged)
0x0C 0x0F	Player	Current	(unchanged)
0x0D 0x10	Player Position	Current	(unchanged)
0x0E 0x11	Player Position And Look (serverbound)	Current	(unchanged)
0x0F 0x12	Player Look	Current	(unchanged)
0x10 0x13	Vehicle Move (serverbound)	Current	(unchanged)
0x11 0x14	Steer Boat	Current	(unchanged)
0x15	Pick Item		Pre
0x12 0x16	Craft Recipe Request	Current	Pre
0x13 0x17	Player Abilities (serverbound)	Current	(unchanged)
0x14 0x18	Player Digging	Current	(unchanged)
0x15 0x19	Entity Action	Current	(unchanged)
0x16 0x1A	Steer Vehicle	Current	(unchanged)
0x17 0x1B	Recipe Book Data	Current	Pre
0x1C	Name Item		Pre
0x18 0x1D	Resource Pack Status	Current	(unchanged)
0x19 0x1E	Advancement Tab	Current	(unchanged)
0x1F	Select Trade		Pre
0x20	Set Beacon Effect		Pre
0x1A 0x21	Held Item Change (serverbound)	Current	(unchanged)
0x22	Update Command Block		Pre
0x23	Update Command Block Minecart		Pre
0x1B 0x24	Creative Inventory Action	Current	(unchanged)
0x25	Update Structure Block		Pre
0x1C 0x26	Update Sign	Current	(unchanged)
0x1D 0x27	Animation (serverbound)	Current	(unchanged)
0x1E 0x28	Spectate	Current	(unchanged)
0x1F 0x29	Player Block Placement	Current	(unchanged)
0x20 0x2A	Use Item	Current	(unchanged)
Login clientbound
0x00	Login Plugin Request		Pre
0x00 0x01	Disconnect (login)	Current	(unchanged)
0x01 0x02	Encryption Request	Current	(unchanged)
0x02 0x03	Login Success	Current	(unchanged)
0x03 0x04	Set Compression	Current	(unchanged)
Login serverbound
0x00	Login Plugin Response		Pre
0x00 0x01	Login Start	Current	(unchanged)
0x01 0x02	Encryption Response	Current	(unchanged)

New/modified data types

Slot

Name	Type	Meaning
Block ID Item ID	Short	The item/block ID. A value of -1 signifies that the slot is empty, and no further data follows. Item IDs are now uniquely defined and are completely independent of block IDs.
Item Count	Optional Byte	Not present if Block ID is -1.
Item Damage	Optional Short	Not present if Block ID is -1.
NBT	Optional NBT	Not present if Block ID is -1. If 0, there is no NBT data, and no further data follows. Otherwise the byte is the start of an NBT blob as shown below:

Particle

Field Name	Field Type	Meaning
ID	VarInt	The ID of the particle type, see below.
Data	Varies	Varies based on the particle type, see below.

Particle Name	Particle ID	Data
minecraft:ambient_entity_effect	0	None
minecraft:angry_villager	1	None
minecraft:barrier	2	None
minecraft:block	3	Field Name Field Type Meaning BlockState VarInt The ID of the block state.
minecraft:bubble	4	None
minecraft:cloud	5	None
minecraft:crit	6	None
minecraft:damage_indicator	7	None
minecraft:dragon_breath	8	None
minecraft:dripping_lava	9	None
minecraft:dripping_water	10	None
minecraft:dust	11	Field Name Field Type Meaning Red Float Red value, 0-1 Green Float Green value, 0-1 Blue Float Blue value, 0-1 Scale Float The scale, will be clamped between 0.01 and 4.
minecraft:effect	12	None
minecraft:elder_guardian	13	None
minecraft:enchanted_hit	14	None
minecraft:enchant	15	None
minecraft:end_rod	16	None
minecraft:entity_effect	17	None
minecraft:explosion_emitter	18	None
minecraft:explosion	19	None
minecraft:falling_dust	20	Field Name Field Type Meaning BlockState VarInt The ID of the block state.
minecraft:firework	21	None
minecraft:fishing	22	None
minecraft:flame	23	None
minecraft:happy_villager	24	None
minecraft:heart	25	None
minecraft:instant_effect	26	None
minecraft:item	27	Field Name Field Type Meaning Item Slot The item that will be used.
minecraft:item_slime	28	None
minecraft:item_snowball	29	None
minecraft:large_smoke	30	None
minecraft:lava	31	None
minecraft:mycelium	32	None
minecraft:note	33	None
minecraft:poof	34	None
minecraft:portal	35	None
minecraft:rain	36	None
minecraft:smoke	37	None
minecraft:spit	38	None
minecraft:squid_ink	39	None
minecraft:sweep_attack	40	None
minecraft:totem_of_undying	41	None
minecraft:underwater	42	None
minecraft:splash	43	None
minecraft:witch	44	None
minecraft:bubble_pop	45	None
minecraft:current_down	46	None
minecraft:bubble_column_up	47	None
minecraft:nautilus	48	None
minecraft:dolphin	49	None

Chat

Selector component

Displays the results of an entity selector. Should not be sent to clients; only intended for commands and client-to-server actions. If the component contains a selector key, then it is a selector component.

The server resolves the list selector into a list of entities, each with an appropriate hover event, and joined with commas and "and" (but it lacks a serial comma) joined with commas between each entry, without an "and".

Entity Metadata Format

Note that entity metadata is a totally distinct concept from block metadata. It is not required to send all metadata fields, or even any metadata fields, so long as the terminating entry is correctly sent.

Entity Metadata is an array of entries, each of which looks like the following:

Name	Type	Meaning
Index	Unsigned Byte	Unique index key determining the meaning of the following value, see the table below. If this is 0xff then the it is the end of the Entity Metadata array and no more is read.
Type	Optional Byte Enum	Only if Index is not 0xff; the type of the index, see the table below
Value	Optional value of Type	Only if Index is not 0xff: the value of the metadata field

Value of Type field	Type of Value field	Notes
0	Byte
1	VarInt
2	Float
3	String
4	Chat
5	OptChat (Boolean + Optional Chat)	Chat is present if the Boolean is set to true
5 6	Slot
6 7	Boolean
7 8	Rotation	3 floats: rotation on x, rotation on y, rotation on z
8 9	Position
9 10	OptPosition (Boolean + Optional Position)	Position is present if the Boolean is set to true
10 11	Direction (VarInt)	(Down = 0, Up = 1, North = 2, South = 3, West = 4, East = 5)
11 12	OptUUID (Boolean + Optional UUID)	UUID is present if the Boolean is set to true
12 13	OptBlockID (VarInt)	0 for absent, otherwise index into the global palette. (Air is treated as absent)
13 14	NBT Tag
15	#Particle

Entity

The base class.

Index	Type	Meaning		Default
0	Byte	Bit mask	Meaning	0
		0x01	On Fire
		0x02	Crouched
		0x04	Unused (previously riding)
		0x08	Sprinting
		0x10	Unused (previously eating/drinking/blocking; use hand state now)
		0x20	Invisible
		0x40	Glowing effect
		0x80	Flying with elytra
1	VarInt	Air		300
2	String OptChat	Custom name		empty
3	Boolean	Is custom name visible		false
4	Boolean	Is silent		false
5	Boolean	No gravity		false

AreaEffectCloud

Extends Entity.

Index	Type	Meaning		Default
6	Float	Radius		0.5
7	VarInt	Color (only for mob spell particle)		0
8	Boolean	Ignore radius and show effect as single point, not area		false
9	Particle	The #Particle		effect
9	VarInt	Particle ID		15 (mobSpell)
10	VarInt	Particle parameter 1		0
11	VarInt	Particle parameter 2		0

Trident

Extends Arrow.

Index	Type	Meaning		Default
7	VarInt	Loyalty level (enchantment)		0

Boat

Extends Entity.

Index	Type	Meaning		Default
6	VarInt	Time since last hit		0
7	VarInt	Forward direction		1
8	Float	Damage taken		0.0
9	VarInt	Type (0=oak, 1=spruce, 2=birch, 3=jungle, 4=acacia, 5=dark oak)		0
10	Boolean	Right paddle turning		false
11	Boolean	Left paddle turning		false
12	VarInt	Splash timer (?)		0

Phantom

Extends Flying.

Index	Type	Meaning		Default
12	VarInt	Size		0

Hitbox size is determined by horizontal=0.9 + 0.2*size and vertical=0.5 + 0.1 * i

Dolphin

Extends Creature.

No additional metadata.

WaterMob

Extends Insentient Creature.

No additional metadata.

Abstract fish

Extends WaterMob.

Index	Type	Meaning		Default
12	Boolean	From bucket		False

Cod

Extends AbstractFish.

No additional metadata.

Puffer fish

Extends AbstractFish.

Index	Type	Meaning		Default
13	VarInt	PuffState (varies from 0 to 2)		0

Salmon

Extends AbstractFish.

No additional metadata.

Tropical fish

Extends AbstractFish.

Index	Type	Meaning		Default
13	VarInt	Variant		0

Turtle

Extends Animal.

Index	Type	Meaning		Default
13	BlockPos	Home pos		(0, 0, 0)
14	Boolean	Has egg		false
15	Boolean	Laying egg (?)		false
16	BlockPos	Travel pos		(0, 0, 0)
17	Boolean	Going home		false
18	Boolean	Traveling		false

Drowned

Extends Drowned.

Index	Type	Meaning		Default
15	Boolean	Has target (?)		false

Block Actions

No changes so far.

Plugin Channels

All clientbound channels have been renamed to be namespaced identifiers.

minecraft:register

Formerly REGISTER.

minecraft:unregister

Formerly UNREGISTER.

minecraft:brand

Formerly MC|Brand.

minecraft:book_open

Formerly MC|BOpen.

minecraft:trader_list

Formerly MC|TrList.

MC|StopSound

Server to client

Used to implement the /stopsound command. Stops a sound that is currently playing on the client.

Field name	Field type	Notes
Sound category	String	Should be one of the sound categories used in Named Sound Effect, but if it's invalid or empty then it is (intentionally) treated as all sound categories.
Sound name	String	A sound effect name. If left empty, all sounds are stopped.

Emptiness of sound category or sound name can be combined, IE a empty sound name but a set sound category will stop all sounds in the given category.

This plugin channel has been replaced by the stop sound packet.

minecraft:debug/paths

Formerly MC|DebugPath.

minecraft:debug/neighbors_update

Formerly MC|DebugNeighborsUpdate.

minecraft:debug/caves

Never sent, but (presumably) used to debug caves. Does not render without modifying the client.

Field name		Field type		Notes
Unknown 1		Position
Count		Int		Number of elements in the following array
Data	Unknown 2	Array	Position
	Unknown 3		Float

minecraft:debug/structures

Never sent, but (presumably) used to debug structures. Does not render without modifying the client.

Field name		Field type		Notes
Unknown 1		Int
Bounding box minX		Int		min must be less than max
Bounding box minY		Int
Bounding box minZ		Int
Bounding box maxX		Int
Bounding box maxY		Int
Bounding box maxZ		Int
Count		Int		Number of elements in the following array
Unknown	Bounding box minX	Array	Int	min must be less than max
	Bounding box minY		Int
	Bounding box minZ		Int
	Bounding box maxX		Int
	Bounding box maxY		Int
	Bounding box maxZ		Int
	Unknown		Boolean

minecraft:debug/worldgen_attempt

Never sent, but (presumably) used to debug something with world generation. Does not render without modifying the client.

This channel is invalid, as its name is longer than the max length (23 > 20).

Field name	Field type	Notes
Unknown 1	Position
Unknown 2	Float
Unknown 3	Float
Unknown 4	Float
Unknown 5	Float
Unknown 6	Float

Play

Clientbound

Spawn Painting

This packet shows location, name, and type of painting.

Packet ID	State	Bound To	Field Name	Field Type	Notes
0x04	Play	Client	Entity ID	VarInt
			Entity UUID	UUID
			Motive	String (13) VarInt	Name of the painting. Max length 13 Panting's ID, see below
			Location	Position	Center coordinates (see below)
			Direction	Byte Enum	Direction the painting faces (North = 2, South = 0, West = 1, East = 3)

Calculating the center of an image: given a (width × height) grid of cells, with (0, 0) being the top left corner, the center is (max(0, width / 2 - 1), height / 2). E.g. (1, 0) for a 2×1 painting, or (1, 2) for a 4×4 painting.

List of paintings by coordinates in paintings_kristoffer_zetterstrand.png (where x and y are in pixels from the top left and width and height are in pixels or 16ths of a block):

Name	ID	x	y	width	height
Kebab minecraft:kebab	0	0	0	16	16
Aztec minecraft:aztec	1	16	0	16	16
Alban minecraft:alban	2	32	0	16	16
Aztec2 minecraft:aztec2	3	48	0	16	16
Bomb minecraft:bomb	4	64	0	16	16
Plant minecraft:plant	5	80	0	16	16
Wasteland minecraft:wasteland	6	96	0	16	16
Pool minecraft:pool	7	0	32	32	16
Courbet minecraft:courbet	8	32	32	32	16
Sea minecraft:sea	9	64	32	32	16
Sunset minecraft:sunset	10	96	32	32	16
Creebet minecraft:creebet	11	128	32	32	16
Wanderer minecraft:wanderer	12	0	64	16	32
Graham minecraft:graham	13	16	64	16	32
Match minecraft:match	14	0	128	32	32
Bust minecraft:bust	15	32	128	32	32
Stage minecraft:stage	16	64	128	32	32
Void minecraft:void	17	96	128	32	32
SkullAndRoses skull_and_roses	18	128	128	32	32
Wither minecraft:wither	19	160	128	32	32
Fighters minecraft:fighters	20	0	96	64	32
Pointer minecraft:pointer	21	0	192	64	64
Pigscene minecraft:pigscene	22	64	192	64	64
BurningSkull minecraft:burning_skull	23	128	192	64	64
Skeleton minecraft:skeleton	24	192	64	64	48
DonkeyKong minecraft:donkey_kong	25	192	112	64	48

The Minecraft Wiki article on paintings also provides a list of painting names to the actual images.

Statistics

Sent as a response to Client Status (id 1).

Packet ID	State	Bound To	Field Name		Field Type		Notes
0x07	Play	Client	Count		VarInt		Number of elements in the following array
			Statistic	Name	Array	String (32767)	https://gist.github.com/Alvin-LB/8d0d13db00b3c00fd0e822a562025eff
				Category ID		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.sneak_Time	3	Time
minecraft.walk_one_cm	4	Distance
minecraft.crouch_one_cm	5	Distance
minecraft.sprint_one_cm	6	Distance
minecraft.swim_one_cm	7	Distance
minecraft.fall_one_cm	8	Distance
minecraft.climb_one_cm	9	Distance
minecraft.fly_one_cm	10	Distance
minecraft.dive_one_cm	11	Distance
minecraft.minecart_one_cm	12	Distance
minecraft.boat_one_cm	13	Distance
minecraft.pig_one_cm	14	Distance
minecraft.horse_one_cm	15	Distance
minecraft.aviate_one_cm	16	Distance
minecraft.jump	17	None
minecraft.drop	18	None
minecraft.damage_dealt	19	Damage
minecraft.damage_taken	20	Damage
minecraft.deaths	21	None
minecraft.mob_kills	22	None
minecraft.animals_bred	23	None
minecraft.player_kills	24	None
minecraft.fish_caught	25	None
minecraft.talked_to_villager	26	None
minecraft.traded_with_villager	27	None
minecraft.eat_cake_slice	28	None
minecraft.fill_cauldron	29	None
minecraft.use_cauldron	30	None
minecraft.clean_armor	31	None
minecraft.clean_banner	32	None
minecraft.interact_with_brewingstand	33	None
minecraft.interact_with_beacon	34	None
minecraft.inspect_dropper	35	None
minecraft.inspect_hopper	36	None
minecraft.inspect_dispenser	37	None
minecraft.play_noteblock	38	None
minecraft.tune_noteblock	39	None
minecraft.pot_flower	40	None
minecraft.trigger_trapped_chest	41	None
minecraft.open_enderchest	42	None
minecraft.enchant_item	43	None
minecraft.play_record	44	None
minecraft.interact_with_furnace	45	None
minecraft.interact_with_crafting_table	46	None
minecraft.open_chest	47	None
minecraft.sleep_in_bed	48	None
minecraft.open_shulker_box	49	None

Units:

• 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

Update Block Entity

Sets tile entity associated with the block at the given location.

Packet ID	State	Bound To	Field Name	Field Type	Notes
0x09	Play	Client	Location	Position
			Action	Unsigned Byte	The type of update to perform, see below
			NBT Data	NBT Tag	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)

Action field:

• 1: Set data of a mob spawner (everything except for SpawnPotentials: current delay, min/max delay, mob to be spawned, spawn count, spawn range, etc.)
• 2: Set command block text (command and last execution status)
• 3: Set the level, primary, and secondary powers of a beacon
• 4: Set rotation and skin of mob head
• 5: Set type of flower in flower pot
• 5: Declare a conduit
• 6: Set base color and patterns on a banner
• 7: Set the data for a Structure tile entity
• 8: Set the destination for a end gateway
• 9: Set the text on a sign
• 10: Declare a shulker box, no data appears to be sent and the client seems to do fine without this packet. Perhaps it is a leftover from earlier versions?
• 11: Set the color of a bed Declare a bed

Block Change

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
0x0B	Play	Client	Location	Position	Block Coordinates
			Block ID	VarInt	The new block state ID for the block as given in the global palette. (When reading data: type = id >> 4, meta = id & 15, when writing data: id = type << 4 | (meta & 15)) See that section for more information.

Multi Block Change

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 Change).

Packet ID	State	Bound To	Field Name		Field Type		Notes
0x10 0x0F	Play	Client	Chunk X		Int		Chunk X coordinate
			Chunk Z		Int		Chunk Z coordinate
			Record Count		VarInt		Number of elements in the following array, i.e. the number of blocks affected
			Record	Horizontal Position	Array	Unsigned Byte	The 4 most significant bits (0xF0) encode the X coordinate, relative to the chunk. The 4 least significant bits (0x0F) encode the Z coordinate, relative to the chunk.
				Y Coordinate		Unsigned Byte	Y coordinate of the block
				Block ID		VarInt	The new block state ID for the block as given in the global palette. (When reading data: type = id >> 4, meta = id & 15, when writing data: id = type << 4 | (meta & 15)) See that section for more information.

To decode the position into a world position:

worldX = (horizPos >> 4 & 15) + (chunkX * 16);
worldY = vertPos;
worldZ = (horizPos & 15) + (chunkZ * 16);

Tab-Complete (clientbound)

Used to respond to the client's previous tab complete request.

Packet ID	State	Bound To	Field Name		Field Type		Notes
0x0E 0x10	Play	Client	Transaction Id		VarInt		This id should also be used in the tab completion response packet, or it will be ignored.
			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 command 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 Chat	Tooltip to display; only present if previous Boolean is true

Declare 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.

Plugin Message (clientbound)

Main article: Plugin channels

Mods and plugins can use this to send their data. Minecraft itself uses a number of plugin channels. These internal channels are prefixed with MC|.

More documentation on this: http://dinnerbone.com/blog/2012/01/13/minecraft-plugin-channels-messaging/

Packet ID	State	Bound To	Field Name	Field Type	Notes
0x18 0x19	Play	Client	Channel	String (20) Identifier	Name of the plugin channel used to send the data
			Data	Byte Array	Any data, depending on the channel. MC| channels are documented here. The length of this array must be inferred from the packet length.

Named Sound Effect

See also: #Sound Effect

Used to play a sound effect on the client. Custom sounds may be added by resource packs.

Packet ID	State	Bound To	Field Name	Field Type	Notes
0x19 0x1A	Play	Client	Sound Name	String (256) Identifier	All sound effect names as of 1.12.2 can be seen here.
			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 is 100%, can be more
			Pitch	Float	Float between 0.5 and 2.0 by Notchian clients

NBT Query Response

Sent in response to Query Block NBT or Query Entity NBT.

Packet ID	State	Bound To	Field Name	Field Type	Notes
0x1D	Play	Client	Transaction ID	VarInt	Can be compared to the one sent in the original query packet.
			NBT	NBT Tag	The NBT of the block or entity. May be a TAG_END (0) in which case no NBT is present.

Chunk Data

Main article: Chunk Format

See also: #Unload Chunk

The server only sends skylight information for chunk pillars in the Overworld, it's up to the client to know in which dimenison the player is currently located. You can also infer this information from the primary bitmask and the amount of uncompressed bytes sent. This packet also sends all block entities in the chunk (though sending them is not required; it is still legal to send them with Update Block Entity later).

Indexes into the global palette are still used, but since the global palette has changed, behavior is different. The Palette length field is no longer sent when using the global palette

The bits per block value used to index in the global palette is 13 14, which is determined by taking the base 2 logarithm of the highest state ID and then rounding up (or alternatively, simply checking how many bits are needed to represent the highest state ID).

Packet ID	State	Bound To	Field Name	Field Type	Notes
0x20 0x22	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)
			Ground-Up Continuous	Boolean	See Chunk Format
			Primary Bit Mask	VarInt	Bitmask with bits set to 1 for every 16×16×16 chunk section whose data is included in Data. The least significant bit represents the chunk section at the bottom of the chunk column (from y=0 to y=15).
			Size	VarInt	Size of Data in bytes
			Data	Byte array	See data structure in Chunk Format
			Number of block entities	VarInt	Number of elements in the following array
			Block entities	Array of NBT Tag	All block entities in the chunk. Use the x, y, and z tags in the NBT to determine their positions.

The chunk data packet currently (for 1.13 snapshots) may allocate a data array slightly larger than necessary; see MC-131684. As such, there may be extra data (all zeros) after the end of the buffer that is not used.

Data structure

The data section of the packet contains most of the useful data for the chunk.

Field Name	Field Type	Notes
Data	Array of Chunk Section	The number of elements is equal to the number of bits set in Primary Bit Mask. Sections are sent bottom-to-top, i.e. the first section, if sent, extends from Y=0 to Y=15.
Biomes	Optional Byte Int Array	Only sent if Ground-Up Continuous is true; 256 bytes entries if present

Direct palette

This format is used for bits per block values greater than 9. The number of bits used to represent a block are the base 2 logarithm of the number of block states, rounded up. For the current vanilla release, this is 13 bits per block.

The "palette" uses the following format:

Field Name	Field Type	Notes
Dummy Palette Length	VarInt	Should always be 0. Only exists to mirror the format used elsewhere.
no fields

If Minecraft Forge is installed and a sufficiently large number of blocks are added, the bits per block value for the global palette will be increased to compensate for the increased ID count. This increase can go up to 16 bits per block (for a total of 4096 block IDs; when combined with the 16 damage values, there are 65536 total states). You can get the number of blocks with the "Number of ids" field found in the RegistryData packet in the Forge Handshake.

Spawn Particle

Displays the named particle

Packet ID	State	Bound To	Field Name	Field Type	Notes
0x22 0x24	Play	Client	Particle ID	Int	The particle ID listed in #Particle.
			Long Distance	Boolean	If true, particle distance increases from 256 to 65536
			X	Float	X position of the particle
			Y	Float	Y position of the particle
			Z	Float	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()
			Particle Data	Float	The data of each particle
			Particle Count	Int	The number of particles to create
			Data	Array of VarInt Varies	Length depends on particle. "iconcrack" has length of 2, "blockcrack", "blockdust", and "fallingdust" have lengths of 1, the rest have 0. The variable data listed in #Particle

Map

Updates a rectangular area on a map item.

Packet ID	State	Bound To	Field Name		Field Type		Notes
0x24 0x26	Play	Client	Item Damage		VarInt		The damage value (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)
			Tracking Position		Boolean		Specifies whether the icons are shown
			Icon Count		VarInt		Number of elements in the following array
			Icon	Direction And Type Type	Array	Byte VarInt enum	0xF0 = Type, 0x0F = Direction Type (see below)
				X		Byte
				Z		Byte
				Direction		Byte	0-15
				Has Display Name		Boolean
				Display Name		Optional Chat	Only present if previous Boolean is true
			Columns		Byte		Number of columns updated
			Rows		Optional Byte		Only if Columns is more than 0; number of rows updated
			X		Optional Byte		Only if Columns is more than 0; x offset of the westernmost column
			Z		Optional 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	Temple
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

Craft Recipe Response

Response to the serverbound packet (Craft Recipe Request), with the same recipe ID. Appears to be used to notify the UI.

Packet ID	State	Bound To	Field Name	Field Type	Notes
0x2B 0x2D	Play	Client	Window ID	Byte
			Recipe	VarInt Identifer	A recipe ID

Face Player

Used to rotate the client player to face the given location or entity (for /teleport [<targets>] <x> <y> <z> facing).

Packet ID	State	Bound To	Field Name	Field Type	Notes
0x31	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.

Unlock Recipes

Packet ID	State	Bound To	Field Name	Field Type	Notes
0x31 0x34	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.
			Array size 1	VarInt	Number of elements in the following array
			Recipe IDs	Array of VarInt Identifier
			Array size 2	Optional VarInt	Number of elements in the following array, only present if mode is 0 (init)
			Recipe IDs	Optional Array of VarInt Identifier, only present if mode is 0 (init)

Action:

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

Scoreboard Objective

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
0x42 0x45	Play	Client	Objective Name	String (16)	An 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 String (32) Chat	Only if mode is 0 or 2. The text to be displayed for the score
			Type	Optional String VarInt Enum	Only if mode is 0 or 2. “integer” or “hearts”

Teams

Creates and updates teams.

Packet ID	State	Bound To	Field Name		Field Type	Notes
0x44 0x47	Play	Client	Team Name		String (16)	A unique name for the team. (Shared with scoreboard).
			Mode		Byte	Determines the layout of the remaining packet
			0: create team	Team Display Name	String (32) Chat
				Team Prefix	String (16)	Displayed before the names of players that are part of this team
				Team Suffix	String (16)	Displayed after the names of players that are part of this team
				Friendly Flags	Byte	Bit mask. 0x01: Allow friendly fire, 0x02: can see invisible players on same team
				Name Tag Visibility	String Enum (32)	always, hideForOtherTeams, hideForOwnTeam, never
				Collision Rule	String Enum (32)	always, pushOtherTeams, pushOwnTeam, never
				Color Formatting	Byte VarInt enum	For colors, the same Chat colors (0-15). -1 indicates RESET/no color. See below for more info.
				Team Prefix	Chat	Displayed before the names of players that are part of this team
				Team Suffix	Chat	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 (40)	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	String (32) Chat
				Team Prefix	String (16)	Displayed before the names of entities that are part of this team
				Team Suffix	String (16)	Displayed after the names of entities that are part of this team
				Friendly Flags	Byte	Bit mask. 0x01: Allow friendly fire, 0x02: can see invisible entities on same team
				Name Tag Visibility	String Enum (32)	always, hideForOtherTeams, hideForOwnTeam, never
				Collision Rule	String Enum (32)	always, pushOtherTeams, pushOwnTeam, never
				Color Formatting	Byte VarInt enum	For colors, the same Chat colors (0-15). -1 indicates RESET/no color. See below for more info.
				Team Prefix	Chat	Displayed before the names of players that are part of this team
				Team Suffix	Chat	Displayed after the names of players that are part of this team
			3: add players to team	Entity Count	VarInt	Number of elements in the following array
				Entities	Array of String (40)	Identifiers for the entities added. For players, this is their username; for other entities, it is their UUID.
			4: remove players from team	Entity Count	VarInt	Number of elements in the following array
				Entities	Array of String (40)	Identifiers for the entities removed. For players, this is their username; for other entities, it is their UUID.

Formatting: The formatting of a team defines how the names of the team members are visualized. The following table lists all the possible formattings.

ID	Formatting
0-15	Color formatting, same values as Chat colors.
16	Obfuscated
17	Bold
18	Strikethrough
19	Underlined
20	Italic
21	Reset

Stop Sound

Packet ID	State	Bound To	Field Name	Field Type	Notes
0x4C	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 Named Sound Effect. If not present, then all sounds are cleared.

Categories:

Name	Value
master	0
music	1
record	2
weather	3
block	4
hostile	5
neutral	6
player	7
ambient	8
voice	9

Declare Recipes

Packet ID	State	Bound To	Field Name		Field Type		Notes
0x54	Play	Client	Num Recipes		VarInt		Number of elements in the following array
			Recipe	Recipe ID	Array	Identifier
				Type		String	The recipe type, see below
				Data		Optional, varies	Additional data for the recipe. For some types, there will be no data.

Recipe types:

Type	Description	Data
crafting_shapeless	Shapeless crafting recipe. All items in the ingredient list must be present, but in any order/slot.	As follows: Name Type Description Group String Used to group similar recipes together in the recipe book. Tag is present in recipe JSON. Ingredient count VarInt Number of elements in the following array Ingredients Array of Ingredient Result Slot
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 Width VarInt Height VarInt Group String Used to group similar recipes together in the recipe book. Tag is present in recipe JSON. Ingredients Array of Ingredient Length is width * height. Indexed by x + (y * width). Result Slot
crafting_special_armordye	Recipe for dying leather armor	None
crafting_special_bookcloning	Recipe for copying contents of written books	None
crafting_special_mapcloning	Recipe for copying maps	None
crafting_special_mapextending	Recipe for adding paper to maps	None
crafting_special_firework_rocket	Recipe for making firework rockets	None
crafting_special_firework_star	Recipe for making firework stars	None
crafting_special_firework_star_fade	Recipe for making firework stars fade between multiple colors	None
crafting_special_repairitem	Recipe for repairing items via crafting	None
crafting_special_tippedarrow	Recipe for crafting tipped arrows	None
crafting_special_bannerduplicate	Recipe for copying banner patterns	None
crafting_special_banneraddpattern	Recipe for adding patterns to banners	None
crafting_special_shielddecoration	Recipe for applying a banner's pattern to a shield	None
crafting_special_shulkerboxcoloring	Recipe for recoloring a shulker box	None
smelting	Smelting recipe	As follows: Name Type Description Group String Used to group similar recipes together in the recipe book. Ingredient Ingredient Result Slot Experience Float Cooking time VarInt

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.

Tags

Packet ID	State	Bound To	Field Name	Field Type	Notes
0x55	Play	Client	Block Tags	(See below)	IDs are block IDs
			Item Tags	(See below)	IDs are item IDs
			Fluid Tags	(See below)	IDs are fluid IDs

Tags 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 ID of the block/item.

Serverbound

Query Block NBT

Used when Shift+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.

Tab-Complete (serverbound)

Sent when the client needs to tab-complete a minecraft:ask_server suggestion type.

Packet ID	State	Bound To	Field Name	Field Type	Notes
0x01 0x05	Play	Server	Transaction Id	VarInt	The id received in the tab completion request packet, must match or the client will ignore this packet. Client generates this and increments it each time it sends another tab completion that doesn't get a response.
			Text	String (32767 256)	All text behind the cursor without the / (e.g. to the left of the cursor in left-to-right languages like English)
			Assume Command	Boolean	If true, the server will parse Text as a command even if it doesn't start with a /. Used in the command block GUI.
			Has Position	Boolean
			Looked At Block	Optional Position	The position of the block being looked at. Only sent if Has Position is true.

Plugin Message (serverbound)

Main article: Plugin channels

Mods and plugins can use this to send their data. Minecraft itself uses a number of plugin channels. These internal channels are prefixed with MC|.

More documentation on this: http://dinnerbone.com/blog/2012/01/13/minecraft-plugin-channels-messaging/

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
0x0A	Play	Server	Channel	String (20) Identifier	Name of the plugin channel used to send the data
			Data	Byte Array	Any data, depending on the channel. MC| channels are documented here. The length of this array must be inferred from the packet length.

Edit Book

Packet ID	State	Bound To	Field Name	Field Type	Notes
0x0B	Play	Server	New book	Slot
			Is signing	Boolean	True if the player is signing the book; false if the player is saving a draft.

When editing a draft, the NBT section of the Slot contains this:

TAG_Compound(''): 1 entry
{
  TAG_List('pages'): 2 entries
  {
    TAG_String(0): 'Something on Page 1'
    TAG_String(1): 'Something on Page 2'
  }
}

When signing the book, it instead looks like this:

TAG_Compound(''): 3 entires
{
  TAG_String('author'): 'Steve'
  TAG_String('title'): 'A Wonderful Book'
  TAG_List('pages'): 2 entries
  {
    TAG_String(0): 'Something on Page 1'
    TAG_String(1): 'Something on Page 2'
  }
}

Query Entity NBT

Used when Shift+F3+I is pressed while looking at an entity.

Packet ID	State	Bound To	Field Name	Field Type	Notes
0x0C	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.

Pick Item

Used to swap out an empty space on the hotbar with the item in the given inventory slot. The Notchain client uses this for pick block functionality (middle click) to retrieve items from the inventory.

Packet ID	State	Bound To	Field Name	Field Type	Notes
0x15	Play	Server	Slot to use	VarInt	See Inventory

The server will first search the player's hotbar for an empty slot, starting from the current slot and looping around to the slot before it. If there are no empty slots, it will start a second search from the current slot and find the first slot that does not contain an enchanted item. If there still are no slots that meet that criteria, then the server will use the currently selected slot.

After finding the appropriate slot, the server swaps the items and then send 3 packets:

• Set Slot, with window ID set to -2 and slot set to the newly chosen slot and the item set to the item that is now in that slot (which was previously at the slot the client requested)
• Set Slot, with window ID set to -2 and slot set to the slot the player requested, with the item that is now in that slot and was previously on the hotbar slot
• Held Item Change, with the slot set to the newly chosen slot.

Craft Recipe Request

A replacement for Prepare Crafting Grid. It appears to behave more or less the same, but the client does not specify where to move the items.

This packet is sent when a player clicks a recipe in the crafting book that is craftable (white border).

Packet ID	State	Bound To	Field Name	Field Type	Notes
0x12 0x16	Play	Server	Window ID	Byte
			Recipe	VarInt Identifier	A recipe ID
			Make all	Boolean	Affects the amount of items processed; true if shift is down when clicked

Recipe Book Data

(previously known as Crafting Book Data)

Packet ID	State	Bound To	Field Name		Field Type	Notes
0x17 0x1B	Play	Server	Type		VarInt	Determines the format of the rest of the packet
			Type	Field Name
			0: Displayed Recipe	Recipe ID	Int Identifer	A recipe ID
			1: Recipe Book States	Crafting Recipe Book Open	Boolean	Whether the player has the crafting recipe book currently opened/active.
				Crafting Recipe Filter Active	Boolean	Whether the player has the crafting recipe book filter option currently active.
				Smelting Recipe Book Open	Boolean	Whether the player has the smelting recipe book currently opened/active.
				Smelting Recipe Filter Active	Boolean	Whether the player has the smelting recipe book filter option currently active.

The Recipe Book Status type is sent when one of the states changes.

Name Item

Sent as a player is renaming an item in an anvil (each keypress in the anvil UI sends a new MC|ItemName Name Item packet). If the new name is empty, then the item loses its custom name (this is different from setting the custom name to the normal name of the item). The item name may be no longer than 35 characters long, and if it is longer than that, then the rename is silently ignored.

Packet ID	State	Bound To	Field Name	Field Type	Notes
0x1C	Play	Server	Item name	String (32767)	The new name of the item

Select Trade

When a player selects a specific trade offered by a villager NPC.

Packet ID	State	Bound To	Field Name	Field Type	Notes
0x1E	Play	Server	Selected slot	Integer VarInt	The selected slot int the players current (trading) inventory. (Was a full Integer for the plugin message)

Set Beacon Effect

Changes the effect of the current beacon.

Packet ID	State	Bound To	Field Name	Field Type	Notes
0x20	Play	Server	Primary Effect	Integer VarInt	A Potion ID. (Was a full Integer for the plugin message)
			Secondary Effect	Integer VarInt	A Potion ID. (Was a full Integer for the plugin message)

Update Command Block

Packet ID	State	Bound To	Field Name	Field Type	Notes
0x22	Play	Server
			X	Int
			Y	Int
			Z	Int
			Location	Position
			Command	String (32767)
			Track output	Boolean	If false, the output of the previous command will not be stored within the command block.
			Mode	String VarInt enum	One of "SEQUENCE" (0), "AUTO" (1), and "REDSTONE" (2)
			Is conditional	Boolean
			Automatic	Boolean
			Flags	Byte	0x01: Track Output (if false, the output of the previous command will not be stored within the command block); 0x02: Is conditional; 0x04: Automatic

Update Command Block Minecart

Packet ID	State	Bound To	Field Name	Field Type	Notes
0x23	Play	Server	Entity ID	Int VarInt
			Command	String
			Track Output	Boolean	If false, the output of the previous command will not be stored within the command block.

Update Structure Block

Packet ID	State	Bound To	Field Name	Field Type	Notes
0x25	Play	Server	X	Int	Tile entity location
			Y	Int	Tile entity location
			Z	Int	Tile entity location
			Location	Position	Block entity location
			Action	Byte VarInt enum	An additional action to perform beyond simply saving the given data; see below
			Mode	String VarInt enum	One of "SAVE" (0), "LOAD" (1), "CORNER" (2), "DATA" (3).
			Name	String
			Offset X	Int Byte	Between -32 and 32
			Offset Y	Int Byte	Between -32 and 32
			Offset Z	Int Byte	Between -32 and 32
			Size X	Int Byte	Between 0 and 32
			Size Y	Int Byte	Between 0 and 32
			Size Z	Int Byte	Between 0 and 32
			Mirror	String VarInt enum	One of "NONE" (0), "LEFT_RIGHT" (1), "FRONT_BACK" (2).
			Rotation	String VarInt enum	One of "NONE" (0), "CLOCKWISE_90" (1), "CLOCKWISE_180" (2), "COUNTERCLOCKWISE_90" (3).
			Metadata	String
			Ignore entities	Boolean
			Show air	Boolean
			Show bounding box	Boolean
			Integrity	Float	Between 0 and 1
			Seed	VarLong
			Flags	Byte	0x01: Ignore entities; 0x02: Show air; 0x04: Show bounding box

Possible actions:

• 1 0 - Update data
• 2 1 - Save the structure
• 3 2 - Load the structure
• 4 3 - Detect size

All other values are ignored. The Notchian client uses 1 update data to indicate no special action should be taken (i.e. the done button).

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 340 390)
			Server Address	String	Hostname or IP, e.g. localhost or 127.0.0.1, that was used to connect. The Notchian server does not use this information.
			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

Status

Clientbound

No changes so far.

Serverbound

No changes so far.

Login

Clientbound

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 vanilla client always responds that it hasn't understood, and sends an empty payload.

Packet ID	State	Bound To	Field Name	Field Type	Notes
0x00	Play	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	Any data, depending on the channel. MC| channels are documented here. The length of this array must be inferred from the packet length.

Serverbound

Login Plugin Response

Packet ID	State	Bound To	Field Name	Field Type	Notes
0x00	Play	Client	Message ID	VarInt	Should match ID from server.
			Successful	Boolean	true if the client understands the request, false otherwise. When false, no payload follows.
			Data	Optional Byte Array	Any data, depending on the channel. MC| channels are documented here. The length of this array must be inferred from the packet length.