HELIX 3 Docs
Web SDK

Web SDK

The canonical TypeScript runtime for HELIX. Build instantly-playable multiplayer worlds for the web — and define the contract every other runtime mirrors.

The Web SDK is HELIX's TypeScript runtime and the canonical API contract. Worlds built here are playable instantly from a link on any device. Everything in the Platform API is available, plus a full multiplayer & networking stack that is specific to the web runtime.

This is the source of truth

The Web SDK's surface is frozen first; the Native (Unreal) SDK mirrors it 1:1. When you read a Platform API page, the Web (TS) tab is the canonical signature.

Packages

PackagePurpose
@helix/sdkThe client SDK — the Helix namespace used in browser/world code.
@helix/server-sdkThe server SDK — HelixInstance and authoritative APIs.
@helix/cliScaffold, run, validate, and deploy worlds.

Client

import { Helix } from '@helix/sdk';

await Helix.init({
  worldId: window.HELIX_WORLD_ID,
  launchTicket: window.HELIX_LAUNCH_TICKET,
});

const me = await Helix.profile.getMyProfile();

From here, the whole Platform API is available on Helix.*, and the networking API on Helix.network / Helix.instance.

Server

Server logic extends HelixInstance and owns authoritative state. The runtime calls your lifecycle hooks:

import { HelixInstance } from '@helix/server-sdk';

export default class MyInstance extends HelixInstance {
  async onCreate(ctx) {}
  async onPlayerJoin(player) {}
  async onPlayerLeave(player) {}
  async onEvent(player, event, payload) {}
  async onTick(dt) {}
  async onClose() {}
}

Get started

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