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github-actions[bot] edited this page Feb 17, 2026 · 1 revision

Interface_ Packets

Version: 2026.02.17-255364b8e

This category contains 33 packet(s).

Packet Index

ID Name Package Compressed Max Size
- PortalState com.hypixel.hytale.protocol.packets.interface_ No 5 bytes
- CustomUIEventBinding com.hypixel.hytale.protocol.packets.interface_ No 31.3 MB
- PortalDef com.hypixel.hytale.protocol.packets.interface_ No 15.6 MB
- CustomUICommand com.hypixel.hytale.protocol.packets.interface_ No 46.9 MB
- BlockChange com.hypixel.hytale.protocol.packets.interface_ No 17 bytes
- ServerPlayerListUpdate com.hypixel.hytale.protocol.packets.interface_ No 32 bytes
- ServerPlayerListPlayer com.hypixel.hytale.protocol.packets.interface_ No 15.6 MB
- FluidChange com.hypixel.hytale.protocol.packets.interface_ No 17 bytes
- EditorSelection com.hypixel.hytale.protocol.packets.interface_ No 24 bytes
0xD2 ServerMessage com.hypixel.hytale.protocol.packets.interface_ No 1600 MB
0xD3 ChatMessage com.hypixel.hytale.protocol.packets.interface_ No 15.6 MB
0xD4 Notification com.hypixel.hytale.protocol.packets.interface_ No 1600 MB
0xD5 KillFeedMessage com.hypixel.hytale.protocol.packets.interface_ No 1600 MB
0xD6 ShowEventTitle com.hypixel.hytale.protocol.packets.interface_ No 1600 MB
0xD7 HideEventTitle com.hypixel.hytale.protocol.packets.interface_ No 4 bytes
0xD8 SetPage com.hypixel.hytale.protocol.packets.interface_ No 2 bytes
0xD9 CustomHud com.hypixel.hytale.protocol.packets.interface_ Yes 1600 MB
0xDA CustomPage com.hypixel.hytale.protocol.packets.interface_ Yes 1600 MB
0xDB CustomPageEvent com.hypixel.hytale.protocol.packets.interface_ No 15.6 MB
0xDE EditorBlocksChange com.hypixel.hytale.protocol.packets.interface_ Yes 132.8 MB
0xDF ServerInfo com.hypixel.hytale.protocol.packets.interface_ No 31.3 MB
0xE0 AddToServerPlayerList com.hypixel.hytale.protocol.packets.interface_ No 1600 MB
0xE1 RemoveFromServerPlayerList com.hypixel.hytale.protocol.packets.interface_ No 62.5 MB
0xE2 UpdateServerPlayerList com.hypixel.hytale.protocol.packets.interface_ No 125.0 MB
0xE3 UpdateServerPlayerListPing com.hypixel.hytale.protocol.packets.interface_ No 78.1 MB
0xE4 UpdateKnownRecipes com.hypixel.hytale.protocol.packets.interface_ No 1600 MB
0xE5 UpdatePortal com.hypixel.hytale.protocol.packets.interface_ No 15.6 MB
0xE6 UpdateVisibleHudComponents com.hypixel.hytale.protocol.packets.interface_ No 3.9 MB
0xE7 ResetUserInterfaceState com.hypixel.hytale.protocol.packets.interface_ No -
0xE8 UpdateLanguage com.hypixel.hytale.protocol.packets.interface_ No 15.6 MB
0xE9 WorldSavingStatus com.hypixel.hytale.protocol.packets.interface_ No 1 bytes
0xEA OpenChatWithCommand com.hypixel.hytale.protocol.packets.interface_ No 15.6 MB
0xEB UpdateAnchorUI com.hypixel.hytale.protocol.packets.interface_ Yes 1600 MB

PortalState

Property Value
Compressed No
Fixed Block Size 5 bytes
Variable Field Count 0
Max Size 5 bytes
Variable Block Start 5

Fields

Name Type Offset Size Encoding Nullable
remainingSeconds int 0 4 int32_le No
breaching boolean 4 1 byte No

Layout Notes: Packet consists of a 4-byte integer 'remainingSeconds' and a 1-byte boolean 'breaching'. No nullable bits or variable-length fields.

CustomUIEventBinding

Property Value
Compressed No
Fixed Block Size 3 bytes
Variable Field Count 2
Max Size 31.3 MB
Nullable Bit Field 1 byte(s)
Variable Block Start 11

Fields

Name Type Offset Size Encoding Nullable
type CustomUIEventBindingType 1 1 byte No
selector String - - - Yes
data String - - - Yes
locksInterface boolean 2 1 byte No

Layout Notes: Fixed block contains null bits at offset 0, type at offset 1, boolean at offset 2. Variable data offsets stored at offset + 3 and + 7 respectively, pointing into variable section starting at byte 11.

type enum values:

  • 0 = Activating
  • 1 = RightClicking
  • 2 = DoubleClicking
  • 3 = MouseEntered
  • 4 = MouseExited
  • 5 = ValueChanged
  • 6 = ElementReordered
  • 7 = Validating
  • 8 = Dismissing
  • 9 = FocusGained
  • 10 = FocusLost
  • 11 = KeyDown
  • 12 = MouseButtonReleased
  • 13 = SlotClicking
  • 14 = SlotDoubleClicking
  • 15 = SlotMouseEntered
  • 16 = SlotMouseExited
  • 17 = DragCancelled
  • 18 = Dropped
  • 19 = SlotMouseDragCompleted
  • 20 = SlotMouseDragExited
  • 21 = SlotClickReleaseWhileDragging
  • 22 = SlotClickPressWhileDragging
  • 23 = SelectedTabChanged

PortalDef

Property Value
Compressed No
Fixed Block Size 9 bytes
Variable Field Count 1
Max Size 15.6 MB
Nullable Bit Field 1 byte(s)
Variable Block Start 9

Fields

Name Type Offset Size Encoding Nullable
nameKey String -1 var var_string:utf8 Yes
explorationSeconds int 1 4 int32_le No
breachSeconds int 5 4 int32_le No

Layout Notes: Fixed block contains nullable bits at offset 0, fixed fields at offsets 1-8, variable data (nameKey) at offset 9+

CustomUICommand

Property Value
Compressed No
Fixed Block Size 2 bytes
Variable Field Count 3
Max Size 46.9 MB
Nullable Bit Field 1 byte(s)
Variable Block Start 14

Fields

Name Type Offset Size Encoding Nullable
type CustomUICommandType 1 1 byte No
selector String -1 var var_string:utf8 Yes
data String -1 var var_string:utf8 Yes
text String -1 var var_string:utf8 Yes

Layout Notes: Fixed block contains nullBits at offset 0 and type at offset 1. Offset pointers to variable strings stored at offsets 2, 6, and 10 respectively, pointing into variable section starting at byte 14.

type enum values:

  • 0 = Append
  • 1 = AppendInline
  • 2 = InsertBefore
  • 3 = InsertBeforeInline
  • 4 = Remove
  • 5 = Set
  • 6 = Clear

BlockChange

Property Value
Compressed No
Fixed Block Size 17 bytes
Variable Field Count 0
Max Size 17 bytes
Variable Block Start 17

Fields

Name Type Offset Size Encoding Nullable
x int 0 4 int32_le No
y int 4 4 int32_le No
z int 8 4 int32_le No
block int 12 4 int32_le No
rotation byte 16 1 byte No

Layout Notes: All fields are fixed size and located sequentially from the given offset

ServerPlayerListUpdate

Property Value
Compressed No
Fixed Block Size 32 bytes
Variable Field Count 0
Max Size 32 bytes
Variable Block Start 32

Fields

Name Type Offset Size Encoding Nullable
uuid UUID 0 16 uuid No
worldUuid UUID 16 16 uuid No

Layout Notes: Packet consists of two UUIDs, each 16 bytes, at fixed offsets 0 and 16 respectively. Total size is 32 bytes.

ServerPlayerListPlayer

Property Value
Compressed No
Fixed Block Size 37 bytes
Variable Field Count 1
Max Size 15.6 MB
Nullable Bit Field 1 byte(s)
Variable Block Start 37

Fields

Name Type Offset Size Encoding Nullable
uuid UUID 1 16 uuid No
username String -1 var var_string:utf8 Yes
worldUuid UUID 17 16 uuid Yes
ping int 33 4 int32_le No

Layout Notes: Fixed block contains nullable bits at offset 0, UUIDs at offsets 1 and 17, ping at offset 33. Variable data (username) is located after fixed block at offset 37, with offset pointer stored in variable block if needed.

FluidChange

Property Value
Compressed No
Fixed Block Size 17 bytes
Variable Field Count 0
Max Size 17 bytes
Variable Block Start 17

Fields

Name Type Offset Size Encoding Nullable
x int 0 4 int32_le No
y int 4 4 int32_le No
z int 8 4 int32_le No
fluidId int 12 4 int32_le No
fluidLevel byte 16 1 byte No

Layout Notes: All fields are fixed size and located sequentially from the given offset

EditorSelection

Property Value
Compressed No
Fixed Block Size 24 bytes
Variable Field Count 0
Max Size 24 bytes
Variable Block Start 24

Fields

Name Type Offset Size Encoding Nullable
minX int 0 4 int32_le No
minY int 4 4 int32_le No
minZ int 8 4 int32_le No
maxX int 12 4 int32_le No
maxY int 16 4 int32_le No
maxZ int 20 4 int32_le No

Layout Notes: All fields are fixed-size 4-byte integers at offsets 0, 4, 8, 12, 16, and 20 respectively.

ServerMessage

Property Value
Packet ID 0xD2 (210)
Compressed No
Fixed Block Size 2 bytes
Variable Field Count 1
Max Size 1600 MB
Nullable Bit Field 1 byte(s)
Variable Block Start 2

Fields

Name Type Offset Size Encoding Nullable
type ChatType 1 1 byte No
message FormattedMessage -1 var nested:FormattedMessage Yes

Layout Notes: Fixed block contains nullBits at offset 0 and type at offset 1. message offset is variable, present when nullBits & 0x1 != 0.

type enum values:

  • 0 = Chat

ChatMessage

Property Value
Packet ID 0xD3 (211)
Compressed No
Fixed Block Size 1 bytes
Variable Field Count 1
Max Size 15.6 MB
Nullable Bit Field 1 byte(s)
Variable Block Start 1

Fields

Name Type Offset Size Encoding Nullable
message String -1 var var_string:utf8 Yes

Layout Notes: Fixed block contains nullable bits at offset 0; variable data (message string) stored after fixed block at offset 1

Notification

Property Value
Packet ID 0xD4 (212)
Compressed No
Fixed Block Size 2 bytes
Variable Field Count 4
Max Size 1600 MB
Nullable Bit Field 1 byte(s)
Variable Block Start 18

Fields

Name Type Offset Size Encoding Nullable
message FormattedMessage -1 var nested:FormattedMessage Yes
secondaryMessage FormattedMessage -1 var nested:FormattedMessage Yes
icon String -1 var var_string:utf8 Yes
item ItemWithAllMetadata -1 var nested:ItemWithAllMetadata Yes
style NotificationStyle 1 1 byte No

Layout Notes: Fixed block contains null bits at offset 0, style at offset 1. Variable data offsets stored at fixed offsets 2, 6, 10, 14 respectively, relative to fixed block start. Variable fields are read from variable section starting at offset 18.

style enum values:

  • 0 = Default
  • 1 = Danger
  • 2 = Warning
  • 3 = Success

KillFeedMessage

Property Value
Packet ID 0xD5 (213)
Compressed No
Fixed Block Size 1 bytes
Variable Field Count 3
Max Size 1600 MB
Nullable Bit Field 1 byte(s)
Variable Block Start 13

Fields

Name Type Offset Size Encoding Nullable
killer FormattedMessage -1 var nested:FormattedMessage Yes
decedent FormattedMessage -1 var nested:FormattedMessage Yes
icon String -1 var var_string:utf8 Yes

Layout Notes: Fixed block contains nullable bits at offset 0; offsets to variable data stored at offsets 1, 5, and 9 respectively; variable data starts at byte 13

ShowEventTitle

Property Value
Packet ID 0xD6 (214)
Compressed No
Fixed Block Size 14 bytes
Variable Field Count 3
Max Size 1600 MB
Nullable Bit Field 1 byte(s)
Variable Block Start 26

Fields

Name Type Offset Size Encoding Nullable
fadeInDuration float 1 4 float32_le No
fadeOutDuration float 5 4 float32_le No
duration float 9 4 float32_le No
icon String -1 var var_string:utf8 Yes
isMajor boolean 13 1 byte No
primaryTitle FormattedMessage -1 var nested:FormattedMessage Yes
secondaryTitle FormattedMessage -1 var nested:FormattedMessage Yes

Layout Notes: Fixed block contains nullBits at offset 0, float fields at offsets 1,5,9, boolean at 13. Variable fields stored in variable block starting at offset 26, with offsets stored at fixed positions (14, 18, 22).

HideEventTitle

Property Value
Packet ID 0xD7 (215)
Compressed No
Fixed Block Size 4 bytes
Variable Field Count 0
Max Size 4 bytes
Variable Block Start 4

Fields

Name Type Offset Size Encoding Nullable
fadeOutDuration float 0 4 float32_le No

Layout Notes: Packet consists of a single fixed-size float field at offset 0, total size 4 bytes

SetPage

Property Value
Packet ID 0xD8 (216)
Compressed No
Fixed Block Size 2 bytes
Variable Field Count 0
Max Size 2 bytes
Variable Block Start 2

Fields

Name Type Offset Size Encoding Nullable
page Page 0 1 byte No
canCloseThroughInteraction boolean 1 1 byte No

Layout Notes: Packet consists of 2 fixed bytes: page (byte) and canCloseThroughInteraction (byte as boolean). No nullable bits or variable fields.

page enum values:

  • 0 = None
  • 1 = Bench
  • 2 = Inventory
  • 3 = ToolsSettings
  • 4 = Map
  • 5 = MachinimaEditor
  • 6 = ContentCreation
  • 7 = Custom

CustomHud

Property Value
Packet ID 0xD9 (217)
Compressed Yes
Fixed Block Size 2 bytes
Variable Field Count 1
Max Size 1600 MB
Nullable Bit Field 1 byte(s)
Variable Block Start 2

Fields

Name Type Offset Size Encoding Nullable
clear boolean 1 1 byte No
commands CustomUICommand[] -1 var array:CustomUICommand Yes

Layout Notes: Fixed block contains nullBits at offset 0 and 'clear' boolean at offset 1. Commands array is present when nullBits & 0x1 != 0, with variable length and offset stored in the array length prefix.

CustomPage

Property Value
Packet ID 0xDA (218)
Compressed Yes
Fixed Block Size 4 bytes
Variable Field Count 3
Max Size 1600 MB
Nullable Bit Field 1 byte(s)
Variable Block Start 16

Fields

Name Type Offset Size Encoding Nullable
key String -1 var var_string:utf8 Yes
isInitial boolean 1 1 byte No
clear boolean 2 1 byte No
lifetime CustomPageLifetime 3 1 byte No
commands CustomUICommand[] -1 var array:nested:CustomUICommand Yes
eventBindings CustomUIEventBinding[] -1 var array:nested:CustomUIEventBinding Yes

Layout Notes: Fixed block contains nullable bits at offset 0, fixed booleans at offsets 1-3, variable data offsets stored at offsets 4, 8, 12 respectively, relative to fixed block start. Variable data stored starting at offset 16.

lifetime enum values:

  • 0 = CantClose
  • 1 = CanDismiss
  • 2 = CanDismissOrCloseThroughInteraction

CustomPageEvent

Property Value
Packet ID 0xDB (219)
Compressed No
Fixed Block Size 2 bytes
Variable Field Count 1
Max Size 15.6 MB
Nullable Bit Field 1 byte(s)
Variable Block Start 2

Fields

Name Type Offset Size Encoding Nullable
type CustomPageEventType 1 1 byte No
data String -1 var var_string:utf8 Yes

Layout Notes: Fixed block contains nullable bits at offset 0, type at offset 1. Variable data (if present) starts at offset + 2, with length prefixed by VarInt.

type enum values:

  • 0 = Acknowledge
  • 1 = Data
  • 2 = Dismiss

EditorBlocksChange

Property Value
Packet ID 0xDE (222)
Compressed Yes
Fixed Block Size 30 bytes
Variable Field Count 2
Max Size 132.8 MB
Nullable Bit Field 1 byte(s)
Variable Block Start 38

Fields

Name Type Offset Size Encoding Nullable
selection EditorSelection 1 0 nested:EditorSelection Yes
blocksChange BlockChange[] -1 var array:BlockChange Yes
fluidsChange FluidChange[] -1 var array:FluidChange Yes
blocksCount int 25 4 int32_le No
advancedPreview boolean 29 1 byte No

Layout Notes: Fixed block contains nullable bits at offset 0; offsets to variable data stored at offset + 30 and + 34 respectively; fixed fields at offsets 25 and 29

ServerInfo

Property Value
Packet ID 0xDF (223)
Compressed No
Fixed Block Size 5 bytes
Variable Field Count 2
Max Size 31.3 MB
Nullable Bit Field 1 byte(s)
Variable Block Start 13

Fields

Name Type Offset Size Encoding Nullable
serverName String -1 var var_string:utf8 Yes
motd String -1 var var_string:utf8 Yes
maxPlayers int 1 4 int32_le No

Layout Notes: Fixed block contains null bits at offset 0, maxPlayers at offset 1-4; variable data offsets stored at offset + 5 (serverName) and + 9 (motd)

AddToServerPlayerList

Property Value
Packet ID 0xE0 (224)
Compressed No
Fixed Block Size 1 bytes
Variable Field Count 1
Max Size 1600 MB
Nullable Bit Field 1 byte(s)
Variable Block Start 1

Fields

Name Type Offset Size Encoding Nullable
players ServerPlayerListPlayer[] -1 var nested:ServerPlayerListPlayer Yes

Layout Notes: Fixed block contains 1 byte for null bits at offset 0. If players array is present, it is stored in the variable section starting at offset 1, with count as VarInt followed by serialized ServerPlayerListPlayer elements.

RemoveFromServerPlayerList

Property Value
Packet ID 0xE1 (225)
Compressed No
Fixed Block Size 1 bytes
Variable Field Count 1
Max Size 62.5 MB
Nullable Bit Field 1 byte(s)
Variable Block Start 1

Fields

Name Type Offset Size Encoding Nullable
players UUID[] -1 var array:nested:UUID Yes

Layout Notes: Fixed block contains nullable bits at offset 0; variable data (UUID array) starts at offset 1, with count prefix as VarInt and UUIDs sequentially stored

UpdateServerPlayerList

Property Value
Packet ID 0xE2 (226)
Compressed No
Fixed Block Size 1 bytes
Variable Field Count 1
Max Size 125.0 MB
Nullable Bit Field 1 byte(s)
Variable Block Start 1

Fields

Name Type Offset Size Encoding Nullable
players ServerPlayerListUpdate[] -1 var nested:ServerPlayerListUpdate[] Yes

Layout Notes: Fixed block contains 1 byte for null bits; if players array is present, variable data starts at offset 1, with array length as VarInt followed by serialized ServerPlayerListUpdate entries

UpdateServerPlayerListPing

Property Value
Packet ID 0xE3 (227)
Compressed No
Fixed Block Size 1 bytes
Variable Field Count 1
Max Size 78.1 MB
Nullable Bit Field 1 byte(s)
Variable Block Start 1

Fields

Name Type Offset Size Encoding Nullable
players Map<UUID, Integer> -1 var nested:Map<UUID, Integer> Yes

Layout Notes: Fixed block contains 1 byte for null bits at offset 0. If players map is present, variable data starts at offset 1, containing count as VarInt followed by UUID and Integer pairs.

UpdateKnownRecipes

Property Value
Packet ID 0xE4 (228)
Compressed No
Fixed Block Size 1 bytes
Variable Field Count 1
Max Size 1600 MB
Nullable Bit Field 1 byte(s)
Variable Block Start 1

Fields

Name Type Offset Size Encoding Nullable
known Map<String, CraftingRecipe> -1 var nested:CraftingRecipe Yes

Layout Notes: Fixed block contains 1 byte for null bits at offset 0. The variable block starts at offset 1, containing the serialized map entries. Each entry has a variable-length string key and a nested CraftingRecipe value.

UpdatePortal

Property Value
Packet ID 0xE5 (229)
Compressed No
Fixed Block Size 6 bytes
Variable Field Count 1
Max Size 15.6 MB
Nullable Bit Field 1 byte(s)
Variable Block Start 6

Fields

Name Type Offset Size Encoding Nullable
state PortalState 1 var nested:PortalState Yes
definition PortalDef -1 var nested:PortalDef Yes

Layout Notes: Fixed block contains nullable bits at offset 0; offset to 'definition' stored at fixed block offset 6; 'state' is inline after null bits

UpdateVisibleHudComponents

Property Value
Packet ID 0xE6 (230)
Compressed No
Fixed Block Size 1 bytes
Variable Field Count 1
Max Size 3.9 MB
Nullable Bit Field 1 byte(s)
Variable Block Start 1

Fields

Name Type Offset Size Encoding Nullable
visibleComponents HudComponent[] -1 var array:nested:HudComponent Yes

Layout Notes: Fixed block contains nullable bits at offset 0; variable block starts at byte 1; variable data includes array length (VarInt) and HudComponent entries

ResetUserInterfaceState

Property Value
Packet ID 0xE7 (231)
Compressed No
Variable Field Count 0

UpdateLanguage

Property Value
Packet ID 0xE8 (232)
Compressed No
Fixed Block Size 1 bytes
Variable Field Count 1
Max Size 15.6 MB
Nullable Bit Field 1 byte(s)
Variable Block Start 1

Fields

Name Type Offset Size Encoding Nullable
language String -1 var var_string:utf8 Yes

Layout Notes: Fixed block contains nullable bits at offset 0. If language is present, it is stored as a variable-length UTF-8 string starting immediately after the null bits byte.

WorldSavingStatus

Property Value
Packet ID 0xE9 (233)
Compressed No
Fixed Block Size 1 bytes
Variable Field Count 0
Max Size 1 bytes
Variable Block Start 1

Fields

Name Type Offset Size Encoding Nullable
isWorldSaving boolean 0 1 byte No

Layout Notes: Packet consists of a single boolean field at offset 0, total size 1 byte

OpenChatWithCommand

Property Value
Packet ID 0xEA (234)
Compressed No
Fixed Block Size 1 bytes
Variable Field Count 1
Max Size 15.6 MB
Nullable Bit Field 1 byte(s)
Variable Block Start 1

Fields

Name Type Offset Size Encoding Nullable
command String -1 var var_string:utf8 Yes

Layout Notes: Fixed block contains nullable bits at offset 0; command string offset and length stored in variable section

UpdateAnchorUI

Property Value
Packet ID 0xEB (235)
Compressed Yes
Fixed Block Size 2 bytes
Variable Field Count 3
Max Size 1600 MB
Nullable Bit Field 1 byte(s)
Variable Block Start 14

Fields

Name Type Offset Size Encoding Nullable
anchorId String -1 var var_string:utf8 Yes
clear boolean 1 1 byte No
commands CustomUICommand[] -1 var array:CustomUICommand Yes
eventBindings CustomUIEventBinding[] -1 var array:CustomUIEventBinding Yes

Layout Notes: Fixed block contains nullable bits at offset 0, boolean at offset 1, and offset pointers at fixed positions (offset + 2, 6, 10) to variable data starting at byte 14

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