Crash Course

import { RivetClient } from '@rivet-gg/api';
let rivet = new RivetClient({ token: process.env.RIVET_TOKEN });

// Find a lobby (a new lobby will automatically be created on demand if needed)
let res = await rivet.matchmaker.lobbies.find({ gameModes: ['default'] });

// Connect to the lobby (Rivet automatically manages your SSL)
let ws = new WebSocket(`wss://${res.ports['default'].host}/?token=${res.player.token}`);

// `RIVET_TOKEN` is automatically added to the environment by Rivet.
import { RivetClient } from "@rivet-gg/api";
let rivet = new RivetClient({ token: process.env.RIVET_TOKEN });

// Tell Rivet your server is ready. This gives you time to load maps and
// other data before accepting players.
rivet.matchmaker.lobbies.ready().catch(() => process.exit(1));

myGameServer.on("connect", await (socket) => {
	let playerToken = socket.request.query.token;

	// Notify the matchmaker that the player connected. This can be
	// called only once per player token. This will throw an error and
	// close the socket if the player token is already used or invalid.
	await rivet.matchmaker.players.connected({ playerToken }).catch(err => socket.close());

	socket.on("close", async () => {
		// Notify the matchmaker that the player disconnected.
		await rivet.matchmaker.players.disconnected({ playerToken });
	});
});