Steam Web API Client (@xtsusaku/steamapi-wrapper)

A lightweight, zero-dependency, Bun-first client library for the Steam Web API. This library uses modern JavaScript Proxy objects to dynamically route calls to all 200+ Steam API interfaces and thousands of methods documented on steamapi.xpaw.me, while providing rich TypeScript autocomplete and documentation matching xPaw's site.

Features

• Bun-first / Native ESM: Works out of the box in Bun, Node.js (18+), and standard browsers via native ES Module exports and the built-in fetch API. No dependencies.
• Dynamic Proxy Mapping: Allows you to call any documented or undocumented Steam API interface (e.g. steam.IPlayerService.GetOwnedGames or even publisher-only/custom APIs) dynamically without library updates.
• Auto-formatting of Services: Automatically groups parameters inside the input_json query/body parameters for interfaces ending in "Service", following the official Steam Web API guidelines.
• Service-Aware Array Serialization: Preserves arrays as JSON arrays inside input_json for Service interfaces, and flattens arrays into the zero-indexed format (e.g. steamids[0]=...) only for standard/legacy endpoints.
• Automatic Partner API Routing: Securely routes publisher-only endpoints (e.g. IOnlinePlayService.GetCoPlayStatus) to the Steam partner domain (https://partner.steam-api.com) when a partnerKey is provided.
• Complete Typings: Includes inline TypeScript definitions and JSDoc annotations directly mimicking xPaw's documentation (type, required status, descriptions) for all 200+ interfaces and thousands of endpoints.

Installation

# Using Bun
bun add @xtsusaku/steamapi-wrapper

# Using npm
npm install @xtsusaku/steamapi-wrapper

Usage

Basic Initialization

import { SteamAPI } from "@xtsusaku/steamapi-wrapper";

const steam = new SteamAPI({
  apiKey: "YOUR_STEAM_WEB_API_KEY", // Can be obtained from https://steamcommunity.com/dev/apikey
  partnerKey: "YOUR_PUBLISHER_KEY", // Optional: required for publisher-only endpoints
});

Retrieving Owned Games (IPlayerService)

All Service-based endpoints automatically format parameters using input_json under the hood.

const ownedGames = await steam.IPlayerService.GetOwnedGames({
  steamid: "76561198341746656",
  include_appinfo: true,
  include_played_free_games: true,
});

console.log(ownedGames.response.games);

Retrieving Player Summaries (ISteamUser)

Arrays are automatically flattened to steamids[0], steamids[1], etc., since ISteamUser is a non-Service interface.

const summaries = await steam.ISteamUser.GetPlayerSummaries({
  steamids: ["76561198341746656", "76561197960287930"],
});

console.log(summaries.response.players);

Partner & Publisher-Only Endpoints

Publisher-only endpoints are automatically routed to https://partner.steam-api.com using the partnerKey query parameter. If a developer attempts to call a publisher-only method without providing a partnerKey in the constructor options, a validation error is thrown instantly.

Additionally, if only partnerKey is provided (without an apiKey), the library defaults to routing all API calls (even those that do not normally require a publisher key) to the secure partner host https://partner.steam-api.com using the publisher key.

// Automatically routed to https://partner.steam-api.com/?key=YOUR_PUBLISHER_KEY
const coplayStatus = await steam.IOnlinePlayService.GetCoPlayStatus({
  steamid: "76561198341746656",
  steamid2: "76561197960287930",
  appid: 440,
  time_range_begin: 1700000000,
  time_range_end: 1710000000,
});

Dynamic / Undocumented Endpoints Fallback

If there is a new or undocumented interface not listed in the TypeScript typings, you can still call it directly! The Proxy pattern will resolve it dynamically:

// Call any interface dynamically; type safety falls back to `any` for unknown interfaces
const appDetails = await steam.IStoreService.GetAppList({
  include_games: true,
  max_results: 10,
});

Overriding Versions & HTTP Methods

By default, the library detects if a method is a POST (e.g., if it starts with Set, Add, Remove, Create, etc.) and determines the correct API version (defaulting to v1). If you need to override these defaults, use prefixed underscore parameters:

const response = await steam.ISteamNews.GetNewsForApp({
  appid: 440,
  count: 3,

  // Custom metadata controls (stripped out before sending parameters to Steam)
  _version: 2, // Forces /v2/ instead of /v1/
  _httpMethod: "POST", // Forces POST method instead of GET
});

Configuration Options

The SteamAPI constructor accepts the following options:

| Option | Type | Default | Description | | :------------ | :------- | :------------------------------- | :------------------------------------------------------------------------------ | | apiKey | string | "" | Your Steam Web API Key (for user-level queries) | | partnerKey | string | "" | Your Steamworks Publisher Web API Key (required for publisher-only endpoints) | | accessToken | string | "" | Steam Access Token (for Store/Community APIs) | | baseUrl | string | "https://api.steampowered.com" | Base API host (automatically changed to secure partner host for publisher APIs) | | format | string | "json" | Response format (json, xml, vdf) | | headers | object | {} | Custom headers to pass with every fetch call |

License

This project is licensed under the GNU Affero General Public License v3.0 or later - see the LICENSE file for details.

Contributing

Please read CONTRIBUTING.md for details on our code of conduct, and the process for submitting pull requests to us.