Documentation

Add multiplayer to a web game with one room file — plain TypeScript, the stack you already use, and tests that prove it works. New here? Start with the introduction, or jump straight to the quickstart.

Getting started

Introduction What irt.io is, and the one idea the whole thing is built on.
Quickstart From zero to two tabs sharing a link in five minutes.
Your first room Build a tiny shared-cursors room end to end — schema, room file, client.

Core concepts

The mental model Rooms, ownership, and proving it works — in three sentences.
State & schema The typed description of your shared state — field types, collections, defaults.
Ownership & the ladder Who may write what — and how to move a write from the client to the server.
RPCs Typed calls between client and server for anything that isn't a plain state write.
Server authority & validation Validators, clamping, and the server tick loop — trust without a rewrite.
Presence & lifecycle Joins, leaves, disconnects, and the connection states your UI should handle.

Guides

Retrofit an existing game Add multiplayer to a single-player game without restructuring it.
Co-op movement Client-owned positions with a light server guardrail — the 90% case.
A card game with RPCs Server-owned deck, hidden hands, and moves as typed RPCs.
Authoritative shooter Client inputs, a server tick loop, and prediction for competitive play.

Testing

Simulated players Headless bots that drive your room and assert the resulting state.
Testing in CI Run room tests on every push — fast, deterministic, no services.

Deploy & operate

Deploying a room Ship your room file to production with one command.
The dashboard Live rooms, moderation, usage, and billing at app.irt.io.
Limits & pricing What's metered, the free tier, and the ceilings you should design against.

Reference

CLI Every irtio command — init, dev, test, deploy, and friends.
Client SDK joinRoom, the room handle, state, RPCs, presence, and status.
Room file API defineRoom — lifecycle, validate, rpc, tick, and the context object.
Error catalogue Every typed error the SDK can throw, what causes it, and how to recover.