Login Sequence

Protocol version (Big Endian!)

JSON array of JWT data: contains the display name, UUID and XUID It should be signed by the Mojang public key

Skin related data

Contains the salt to complete the Diffie-Hellman key exchange

Specifies if the disconnection screen should be hidden when the client is disconnected, meaning it will be sent directly to the main menu.

An optional message to show when disconnected.

If the resource pack requires the client accept it.

If scripting is enabled.

A list of behaviour packs that the client needs to download before joining the server. All of these behaviour packs will be applied together.

A list of resource packs that the client needs to download before joining the server. The order of these resource packs is not relevant in this packet. It is however important in the Resource Pack Stack packet.

If the resource pack must be accepted for the player to join the server.

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All of the pack IDs.

NeedsTranslation specifies if any of the messages need to be translated. It seems that where % is found in translatable text types, these are translated regardless of this bool. Translatable text types include TextTypeTip, TextTypePopup and TextTypeJukeboxPopup.

The XUID of the player who sent this message.

PlatformChatID is an identifier only set for particular platforms when chatting (presumably only for Nintendo Switch). It is otherwise an empty string, and is used to decide which players are able to chat with each other.

Time is the current time. The time is not limited to 24000 (time of day), but continues progressing after that.

The unique ID of the player. The unique ID is a value that remains consistent across different sessions of the same world, but most unofficial servers simply fill the runtime ID of the entity out for this field.

The runtime ID of the player. The runtime ID is unique for each world session, and entities are generally identified in packets using this runtime ID.

PlayerGameMode is the game mode the player currently has. It is a value from 0-4, with 0 being survival mode, 1 being creative mode, 2 being adventure mode, 3 being survival spectator and 4 being creative spectator. This field may be set to 5 to make the client fall back to the game mode set in the WorldGameMode field.

The spawn position of the player in the world. In servers this is often the same as the world's spawn position found below.

The pitch and yaw of the player

The seed used to generate the world. Unlike in Java edition, the seed is a 32bit Integer here.

Dimension is the ID of the dimension that the player spawns in. It is a value from 0-2, with 0 being the overworld, 1 being the nether and 2 being the end.

Generator is the generator used for the world. It is a value from 0-4, with 0 being old limited worlds, 1 being infinite worlds, 2 being flat worlds, 3 being nether worlds and 4 being end worlds. A value of 0 will actually make the client stop rendering chunks you send beyond the world limit.

The world game mode that a player gets when it first spawns in the world. It is shown in the settings and is used if the Player Gamemode is set to 5.

Difficulty is the difficulty of the world. It is a value from 0-3, with 0 being peaceful, 1 being easy, 2 being normal and 3 being hard.

The block on which the world spawn of the world. This coordinate has no effect on the place that the client spawns, but it does have an effect on the direction that a compass poInts.

Defines if achievements are disabled in the world. The client crashes if this value is set to true while the player's or the world's game mode is creative, and it's recommended to simply always set this to false as a server.

The time at which the day cycle was locked if the day cycle is disabled using the respective game rule. The client will maIntain this time as Boolean as the day cycle is disabled.

Some Minecraft: Education Edition field that specifies what 'region' the world was from, with 0 being None, 1 being RestOfWorld, and 2 being China. The actual use of this field is unknown.

Specifies if the world has education edition features enabled, such as the blocks or entities specific to education edition.

The level specifying the Intensity of the rain falling. When set to 0, no rain falls at all.

The level specifying the Intensity of the thunder. This may actually be set independently from the rain level, meaning dark clouds can be produced without rain.

Specifies if the world is a multi-player game. This should always be set to true for servers.

Specifies if LAN broadcast was Intended to be enabled for the world.

The mode used to broadcast the joined game across XBOX Live.

The mode used to broadcast the joined game across the platform.

If commands are enabled for the player. It is recommended to always set this to true on the server, as setting it to false means the player cannot, under any circumstance, use a command.

Specifies if the texture pack the world might hold is required, meaning the client was forced to download it before joining.

Defines game rules currently active with their respective values. The value of these game rules may be either 'bool', 'Int32' or 'Float32'. Some game rules are server side only, and don't necessarily need to be sent to the client.

Specifies if the world had the bonus map setting enabled when generating it. It does not have any effect client-side.

Specifies if the world has the start with map setting enabled, meaning each joining player obtains a map. This should always be set to false, because the client obtains a map all on its own accord if this is set to true.

The permission level of the player. It is a value from 0-3, with 0 being visitor, 1 being member, 2 being operator and 3 being custom.

The radius around the player in which chunks are ticked. Most servers set this value to a fixed number, as it does not necessarily affect anything client-side.

Specifies if the texture pack of the world is locked, meaning it cannot be disabled from the world. This is typically set for worlds on the marketplace that have a dedicated texture pack.

Specifies if the texture pack of the world is locked, meaning it cannot be disabled from the world. This is typically set for worlds on the marketplace that have a dedicated texture pack.

Specifies if the world from the server was from a locked world template. For servers this should always be set to false.

Specifies if the world from the server was from a locked world template. For servers this should always be set to false.

Specifies if the world was a template that locks all settings that change properties above in the settings GUI. It is recommended to set this to true for servers that do not allow things such as setting game rules through the GUI.

A hack that Mojang put in place to preserve backwards compatibility with old villagers. The his never actually read though, so it has no functionality.

The version of the game from which Vanilla features will be used. The exact function of this field isn't clear.

A base64 encoded world ID that is used to identify the world.

The name of the world that the player is joining. Note that this field shows up above the player list for the rest of the game session, and cannot be changed. Setting the server name to this field is recommended.

A UUID specific to the premium world template that might have been used to generate the world. Servers should always fill out an empty String for this.

Specifies if the world was a trial world, meaning features are limited and there is a time limit on the world.

RewindHistorySize is the amount of history to keep at maximum if MovementType is packet.AuthoritativeMovementModeServerWithRewind.

ServerAuthoritativeBlockBreaking specifies if block breaking should be sent through packet.PlayerAuthInput or not. This field is somewhat redundant as it is always enabled if MovementType is packet.AuthoritativeMovementModeServer or packet.AuthoritativeMovementModeServerWithRewind

The total time in ticks that has elapsed since the start of the world.

The seed used to seed the random used to produce enchantments in the enchantment table. Note that the exact correct random implementation must be used to produce the correct results both client- and server-side.

A list of all items with their legacy IDs which are available in the game. Failing to send any of the items that are in the game will crash mobile clients.

A unique ID specifying the multi-player session of the player. A random UUID should be filled out for this field.

UUID is the UUID of the player. It is the same UUID that the client sent in the Login packet at the start of the session. A player with this UUID must exist in the player list (built up using the Player List packet) for it to show up in-game.

Username is the name of the player. This username is the username that will be set as the initial name tag of the player.

The unique ID of the player. The unique ID is a value that remains consistent across different sessions of the same world, but most unoffical servers simply fill the runtime ID of the player out for this field.

The runtime ID of the player. The runtime ID is unique for each world session, and entities are generally identified in packets using this runtime ID.

An identifier only set for particular platforms when chatting (presumably only for Nintendo Switch). It is otherwise an empty string, and is used to decide which players are able to chat with each other.

EntityRuntimeID is the runtime ID of the player. The runtime ID is unique for each world session, and entities are generally identified in packets using this runtime ID.

Position is the position to spawn the player on. If the player is on a distance that the viewer cannot see it, the player will still show up if the viewer moves closer.

Pitch is the vertical rotation of the player. Facing straight forward yields a pitch of 0. Pitch is measured in degrees.

Yaw is the horizontal rotation of the player. Yaw is also measured in degrees

HeadYaw is the same as Yaw, except that it applies specifically to the head of the player. A different value for HeadYaw than Yaw means that the player will have its head turned

OnGround specifies if the player is considered on the ground. Note that proxies or hacked clients could fake this to always be true, so it should not be taken for granted.

RiddenEntityRuntimeID is the runtime ID of the entity that the player might currently be riding. If not riding, this should be left 0.

Position is the block position at which a block is updated.

NewBlockRuntimeID is the runtime ID of the block that is placed at Position after sending the packet to the client.

Flags is a combination of flags that specify the way the block is updated client-side. It is a combination of the flags above, but typically sending only the BlockUpdateNetwork flag is sufficient.

Layer is the world layer on which the block is updated. For most blocks, this is the first layer, as that layer is the default layer to place blocks on, but for blocks inside of each other, this differs.

ClientRequestTimestamp is the timestamp on which the client sent this packet to the server. The server should fill out that same value when replying. The ClientRequestTimestamp is always 0

ServerReceptionTimestamp is the timestamp on which the server received the packet sent by the client. When the packet is sent by the client, this value is 0. ServerReceptionTimestamp is generally the current tick of the server. It isn't an actual timestamp, as the field implies

Position is the position of the block that an event occurred at.

EventData holds event type specific data. For chests for example, opening the chest means the data must be 1