Live rooms

A live room connects everyone in an interaction. Zend checks membership, stamps each message with the sender, and fans it out. Nothing is stored, so use the interaction itself for anything you need to keep.

const room = await zend.live.join(game.id);

room.on("presence", (members) => showWhoIsHere(members));
room.on("message", ({ from, data, at }) => applyMove(from, data));
room.on("status", (s) => setBanner(s)); // "connected" | "reconnecting" | "disconnected"
room.on("closed", (reason) => endGame(reason));

await room.send({ move: "A3" });

// later
await room.leave();

Each on call returns a function that removes the handler.

Rules

Only participants of the interaction can join.
from is the sender’s appUserId, set by Zend. A page can’t fake it.
Messages from your server arrive with from: "app". Results of random draws arrive with from: "zend" and data: { type: "random", result }.
Messages are up to 8 KB. Each person can send 20 a second, and each room carries up to 200 a second.
The room closes when the interaction reaches a terminal state. Handlers get closed with a reason.

From your server

Your server can join the same room over WebSocket with your app key, for example to referee a game.

wss://api.usezend.app/api/zend/v2/apps/server/live/<interaction_id>/ws
Authorization: Bearer zapp_sk_...

Send:

{ "type": "send", "data": { "turn": "danny" } }

Receive:

{ "type": "live_message", "interaction_id": "int_...", "from": "zu_...", "data": { "move": "A3" }, "at": "2026-11-02T10:00:00Z" }
{ "type": "live_presence", "interaction_id": "int_...", "members": [ ... ] }
{ "type": "live_closed", "interaction_id": "int_...", "reason": "..." }

Your server can only join rooms for its own app’s interactions.

Get started

Build a ZApp

Money

Fair results

Ship

Examples

Rules

From your server

​Rules

​From your server

Rules

From your server