Skip to content

Server API » Server

The Colyseus Server instance holds the server configuration options, such as transport options, presence, matchmaking driver, etc.

  • Transport is the layer for bidirectional communication between server and client.
  • Presence is the implementation that enables communication between rooms and/or Node.js processes.
  • Driver is the storage driver used for storing and querying rooms during matchmaking.

new Server (options)


Colyseus uses its built-in WebSocket transport by default. See how to customize the transport layer here.


The matchmaking driver. This is where rooms are going to be cached and queried. You must provide a different value than LocalDriver when considering scalability.

Options available are:

  • LocalDriver - default.
  • RedisDriver - available from @colyseus/redis-driver
  • MongooseDriver - available from @colyseus/mongoose-driver


When scaling Colyseus through multiple processes / machines, you need to provide a presence server. Read more about scalability, and the Presence API.

import { Server, RedisPresence } from "colyseus";

const gameServer = new Server({
    // ...
    presence: new RedisPresence()
const colyseus = require("colyseus");

const gameServer = new colyseus.Server({
    // ...
    presence: new colyseus.RedisPresence()


Register shutdown routine automatically. Default is true. If disabled, you should call gracefullyShutdown() method manually in your shutdown process.


Restore previous rooms and states upon server restarting when engaging in iterative development. Default is false. See more in devMode.


This option is going to be deprecated

See WebSocket Transport Options

The HTTP server to bind the WebSocket Server into. You may use express for your server too.

// Colyseus + Express
import { Server } from "colyseus";
import { createServer } from "http";
import express from "express";
const port = Number(process.env.port) || 3000;

const app = express();

const gameServer = new Server({
  server: createServer(app)

// Colyseus + Express
const colyseus = require("colyseus");
const http = require("http");
const express = require("express");
const port = process.env.port || 3000;

const app = express();

const gameServer = new colyseus.Server({
  server: http.createServer(app)

// Colyseus (barebones)
import { Server } from "colyseus";
const port = process.env.port || 3000;

const gameServer = new Server();
// Colyseus (barebones)
const colyseus = require("colyseus");
const port = process.env.port || 3000;

const gameServer = new colyseus.Server();

define (roomName: string, room: Room, options?: any)

Define a new type of room for the matchmaker.


  • roomName: string - The public name of the room. You'll use this name when joining the room from the client-side
  • room: Room - The Room class
  • options?: any - Custom options for room initialization
// Define "chat" room
gameServer.define("chat", ChatRoom);

// Define "battle" room
gameServer.define("battle", BattleRoom);

// Define "battle" room with custom options
gameServer.define("battle_woods", BattleRoom, { map: "woods" });

Defining the same room handler multiple times

You may define the same room handler multiple times with different options. When Room#onCreate() is called, the options will contain the merged values you specified on Server#define() + the options provided when the room is created.

Room definition options


Whenever a room is created by the create() or joinOrCreate() methods, only the options defined by the filterBy() method are going to be stored internally, and used to filter out rooms in further join() or joinOrCreate() calls.


  • options: string[] - a list of option names

Example: allowing different "game modes".

  .define("battle", BattleRoom)

Whenever the room is created, the mode option is going to be stored internally.

client.joinOrCreate("battle", { mode: "duo" }).then(room => {/* ... */});

You can handle the provided option in the onCreate() and/or onJoin() to implement the requested feature inside your room implementation.

class BattleRoom extends Room {
  onCreate(options) {
    if (options.mode === "duo") {
      // do something!
  onJoin(client, options) {
    if (options.mode === "duo") {
      // put this player into a team!

Example: filtering by built-in maxClients

The maxClients is an internal variable stored for matchmaking, and can be used for filtering too.

  .define("battle", BattleRoom)

The client can then ask to join a room capable of handling a certain number of players.

client.joinOrCreate("battle", { maxClients: 10 }).then(room => {/* ... */});
client.joinOrCreate("battle", { maxClients: 20 }).then(room => {/* ... */});


You can also give a different priority for joining rooms depending on their information upon creation.

The options parameter is a key-value object containing the field name in the left, and the sorting direction in the right. Sorting direction can be one of these values: -1, "desc", "descending", 1, "asc" or "ascending".

Example: sorting by the built-in clients

The clients is an internal variable stored for matchmaking, which contains the current number of connected clients. On the example below, the rooms with the highest amount of clients connected will have priority. Use -1, "desc" or "descending" for descending order:

  .define("battle", BattleRoom)
  .sortBy({ clients: -1 });

To sort by the fewest amount of players, you can do the opposite. Use 1, "asc" or "ascending" for ascending order:

  .define("battle", BattleRoom)
  .sortBy({ clients: 1 });

Realtime listing for Lobby

To allow the LobbyRoom to receive updates from a specific room type, you should define them with realtime listing enabled:

  .define("battle", BattleRoom)

See more about the LobbyRoom

Public lifecycle events

You can listen for matchmaking events from outside the room instance scope, such as:

  • "create" - when a room has been created
  • "dispose" - when a room has been disposed
  • "join" - when a client join a room
  • "leave" - when a client leave a room
  • "lock" - when a room has been locked
  • "unlock" - when a room has been unlocked


  .define("chat", ChatRoom)
  .on("create", (room) => console.log("room created:", room.roomId))
  .on("dispose", (room) => console.log("room disposed:", room.roomId))
  .on("join", (room, client) => console.log(, "joined", room.roomId))
  .on("leave", (room, client) => console.log(, "left", room.roomId));


It's completely discouraged to manipulate a room's state through these events. Use the abstract methods in your room handler instead.

removeRoomType (roomName: string)

Revert a .define() call. Makes a roomName unavailable for matchmaking. This method is not recommended but may be helpful in some scenarios.

simulateLatency (milliseconds: number)

This is a convenience method for simulating "lagged" clients during local development.

// Make sure to never call the `simulateLatency()` method in production.
if (process.env.NODE_ENV !== "production") {

  // simulate 200ms latency between server and client.

listen (port: number)

Binds the WebSocket server into the specified port.

onShutdown (callback: Function)

Register a callback that should be called before the process shut down. See graceful shutdown for more details.

gracefullyShutdown (exit: boolean)

Shutdown all rooms and clean-up its cached data. Returns a promise that fulfils whenever the clean-up has been complete.

This method is called automatically unless gracefullyShutdown: false has been provided on Server constructor.