Inventory & UI Packets

Packets in inventory, window, and interface_ packages.

ChatMessage (200)

Bound: Bidirectional

Sends a chat message or command.

Field	Type	Notes
nullBits	Byte	Bitmask.
channel	Byte	0=System, 1=Chat, 2=Whisper.
sender	String	Optional. Sender name.
text	String	Optional. The message content.

Notification (201)

Bound: Clientbound

Shows a UI "Toast" notification.

Field	Type	Notes
title	String	Header text.
message	String	Body text.
icon	String	Asset path for the icon.

KillFeedMessage (202)

Bound: Clientbound

Displays a kill message in the top-right kill feed.

Field	Type	Notes
text	String	The raw text to display.
icon	String	Optional. Path to an icon (e.g. weapon sprite).

WorldSavingStatus (203)

Bound: Clientbound

Shows the "Saving..." icon in the corner.

Field	Type	Notes
active	Boolean	True to show, False to hide.

UpdatePortal (204)

Bound: Clientbound

Updates the visual state of a portal (e.g., Adventure Mode dungeon entrance).

Field	Type	Notes
portalId	Int	Entity ID of the portal.
state	Byte	0=Inactive, 1=Active, 2=Cooling Down.
destination	String	Optional. Name of the destination world.

UpdatePlayerInventory (205)

Bound: Clientbound | Compressed: Yes

Synchronizes the player's local inventory slots.

Field	Type	Notes
nullBits	Byte	Bitmask.
items	Map<Int, ItemStack>	Optional. Slot Index -> Item Data.

MoveItemStack (206)

Bound: Serverbound

Sent when the player drags and drops an item.

Field	Type	Notes
sourceWindow	Int	ID of source container.
sourceSlot	Int	Index in source.
targetWindow	Int	ID of target container.
targetSlot	Int	Index in target.

OpenWindow (208)

Bound: Clientbound

Instructs the client to open a container interface (Chest, Crafting Table).

Field	Type	Notes
windowId	Int	Unique ID for this session.
type	String	Window layout type (e.g., "container_generic_9x3").
title	String	Window title.

CloseWindow (209)

Bound: Bidirectional | State: Play

Sent when a user presses Escape to close a GUI, or by the server to force-close a window.

Field	Type	Notes
windowId	Int	The ID of the window to close.

CustomHud (220)

Bound: Clientbound

Loads a custom HTML/CSS UI layer defined by a script.

Field	Type	Notes
id	String	Unique HUD ID.
html	String	Raw HTML content.
visible	Boolean	Initial visibility.