Network payloads

conduit-render is server-authoritative: every renderable surface flows from the server through one of eight named payloads. The engine ModInitializer registers all of them once; consumer mods don’t touch the registration. This page is a quick reference for what’s on the wire — useful when you’re debugging with a packet sniffer or writing a vanilla-client chat fallback.

When to read this

You’re investigating a “client doesn’t see the screen” bug and want to confirm the payload was sent.
You’re writing tests against the wire format and need to know the type signatures.
You’re considering whether to add a new payload (don’t, if an existing one would do).

Payload types

Screens — `me.zlex.conduit.screen.packet`

Payload	Direction	Body
`ShowScreenPayload`	S → C	`ScreenDef` + `ScreenContent`
`HideScreenPayload`	S → C	screen id (int)
`ButtonClickPayload`	C → S	screen id + button id (string)
`TextInputChangePayload`	C → S	screen id + field id + new value

Labels — `me.zlex.conduit.label.packet`

Payload	Direction	Body
`ShowLabelPayload`	S → C	`LabelDef` + `WorldLabel`
`HideLabelPayload`	S → C	label id (int)

Block displays — `me.zlex.conduit.display.packet`

Payload	Direction	Body
`ShowBlockDisplayPayload`	S → C	id + dimension + pos + item identifier + `BlockDisplaySpec`
`HideBlockDisplayPayload`	S → C	display id (int)

All payloads use FriendlyByteBuf encoding via the element types’ own write/read methods.

Vanilla-client fallback

Every Server*Manager send path gates on ServerPlayNetworking.canSend(player, TYPE). Vanilla clients get a silent no-op — your mod is responsible for sending an equivalent chat-text fallback if non-engine clients matter to your game.

import net.fabricmc.fabric.api.networking.v1.ServerPlayNetworking;
import me.zlex.conduit.screen.packet.ShowScreenPayload;

if (!ServerPlayNetworking.canSend(player, ShowScreenPayload.TYPE)) {
    player.sendSystemMessage(Component.literal("[lobby] " + tagline));
    return;
}

Auto-id ranges

System	Auto-id start	World-wide editor start
Screens	1000	—
Labels	5000	6000
Block displays	9000	10000

Pick stable caller-managed ids outside these ranges to avoid collisions.

Notes

The engine’s payloads are registered by ConduitRenderMod.onInitialize. Don’t re-register them.
Adding a new payload is a new class in the relevant packet subpackage plus a registration line — both well-trodden patterns; copy any existing payload.
If you need a debug log of every payload sent, the easiest place is to add a wrapper around ServerPlayNetworking.send in your own mod rather than mixing into the engine.

Network payloads

When to read this

Payload types

Screens — me.zlex.conduit.screen.packet

Labels — me.zlex.conduit.label.packet

Block displays — me.zlex.conduit.display.packet