Learn Multiplayer Game Development with Colyseus
Tutorials that build a multiplayer game step by step, plus ready-to-run examples for your engine. Further down, open-source demos where one authoritative server drives clients across more than a dozen engines.
Premium Demos
5 complete prototypes you can play right now in your browser. Each runs the whole stack at once: authoritative server, client prediction, smoothed remotes and lag compensation.
We’re actively expanding the set, and adding engine ports to it: Air Hockey already ships Godot and Unity clients alongside its Three.js build.
The source code is the sponsor-only part: these repositories are private, available to Colyseus sponsors.
Become a sponsor for the source code
Open-Source Demos
Every one of these is MIT-licensed and free to clone. Each runs from a single authoritative server with multiple client implementations, one per game engine. Read the source to see exactly how each SDK connects, synchronizes state, and handles real-time gameplay with Colyseus.
Unity, Godot, Defold, GameMaker and Haxe have a client in all three. Whichever you work in, there are three different projects to read in it.
Prediction Playground
colyseus/prediction-playgroundA tour rather than a game: twelve small labs, each isolating one netcode technique. Reconciliation, the interpolation modes, dead reckoning, lag compensation, optimistic events, predicted spawns. Every lab has a live latency slider and shows the exact SDK-facing code it runs.
All twelve labs run on one shared server, so each client below is the same lab logic ported to a different SDK.
Realtime Tanks Multiplayer
colyseus/realtime-tanks-demoA real-time arena shooter: drive, aim and fire against everyone else in the room, with health pickups and a live leaderboard. Nine clients, one server: every row below joins the same match.
Turn-based “UNO” Card Game
colyseus/turnbased-cards-demoA four-player game of UNO: turn order, draw and discard piles, and bots to fill the empty seats. Six clients, one server: every row below sits at the same table.
Framework Overview Talk
Watch Endel Dreyer’s talk at JS GameDev Summit 2022, organized by GitNation. The talk covers how Colyseus handles authoritative game state, client synchronization, and room-based matchmaking.
Going Further
Built your first room? The Netcode section covers the prediction stack: authoritative input, client-side prediction, and lag compensation. These techniques are the built-in version of what the tutorials build by hand.
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