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Mod.io

Mod.io is a cross-platform mod hosting and distribution service. Unlike Steam Workshop, which is tied to Steam, Mod.io works across PC storefronts, consoles, and mobile. If your game ships on multiple platforms or you want a platform-independent modding ecosystem, Mod.io is our top recommendation for studios to add UGC mods.

Mod.io provides a REST API and SDK for most game enginees that both game clients and servers use to discover, download, and manage mods.

The general flow for server-side mod management:

  1. Server queries the Mod.io API for a list of mods (filtered by game, tags, compatibility)
  2. Server downloads mod files directly from Mod.io’s CDN
  3. Server extracts mods to the mods directory
  4. Server loads mods using your mod framework

Mod.io provides endpoints for:

  • Listing mods: Filter by game, tags, popularity, date updated
  • Getting mod details: Version, dependencies, file info, changelog
  • Downloading mod files: Direct CDN links for the mod archive
  • Checking for updates: Compare installed version against latest available

The API uses standard REST with API key authentication. Full documentation is available at docs.mod.io.

Your server needs a Mod.io API key to make requests. Two key types are available:

  • API key (read-only): Sufficient for downloading and listing mods. This is what your server typically needs.
  • OAuth 2 token: Required for write operations (uploading mods, managing subscriptions). Typically used by the game client, not the server.

Store the API key as an environment variable on the server. See Networking and Ports for guidance on managing sensitive data.

Hosting platforms can use the Mod.io API to:

  • Present a mod browser in their admin panel
  • Install and uninstall mods on behalf of server owners
  • Check for mod updates on a schedule
  • Validate mod compatibility with the current server version

Because the API is standard REST, it integrates well with any hosting platform’s automation tooling.

Mod.io’s primary advantage is platform independence. Mods uploaded to Mod.io are available on any platform your game supports, without relying on platform-specific stores. This is particularly valuable if:

  • Your game is on both Steam and the Epic Games Store
  • You plan to support console modding
  • You want a unified mod ecosystem regardless of storefront