Compat API
by FixerLink
With Compat API, a mod author can add cross-mod integrations without hardcoding the compatibility logic, because the library loads the integration code and data packs on its own.
What it does
Compat API is a library for Fabric, Forge and NeoForge that loads integrations only for mods that declare a dependency on it. Integration code, data packs, loot modifiers and conditions are wired in automatically, so a mod that depends on Compat API receives its compat modules without manual setup. The author describes it as a shared standard for the Compat-series mods, including Compat Structure and Compat Artifacts, which both require it.
Installation needs only the Compat API jar on each loader, since integrations are loaded only when the depending mods are present. The server and every player need the mod installed. Files are published for 1.20.1 and 1.21.1, with 1.0.3 as the latest release for each loader, and the code is released under the MIT License but is not open source.
Key features
Automatic compat code loading
Integration code is loaded on its own once a depending mod is present, with no entry points to register by hand.
Automatic data pack injection
Compat data packs are injected into the world without the author editing data pack folders.
Universal loot modifier system
Loot modifiers are wrapped so that integrations can alter drops from other mods through a single interface.
Per-target config toggles
Each integration target can be switched on or off in the config, so a server can leave out a single compat module.
Safe clean system
Integration data is removed cleanly when a mod is absent, so no leftover compat entries remain in the world.
Compatibility
Latest build for each game version and loader.
Only full game releases are shown. This mod publishes no snapshot builds.
Required by 2 mods
Use cases
Who it’s for: Mod authors writing cross-mod integrations, and modpack builders who use the Compat-series mods together.
Questions
Does Compat Structure need Compat API installed?
Which loaders does Compat API support?
Is Compat API needed on a server?
In the catalog
Compat API is one of 3,514 Library mods on ModsFinder, and one of 2,348 Library mods for Fabric. 32,366 mods support Minecraft 1.21.1.
More from FixerLink
Similar mods
What the author says
Compat API is a lightweight and universal compatibility framework for the entire “Compat” ecosystem by fixerlink — including Compat Delight, the upcoming Compat Artifacts, Compat Decor, and any third-party mod that wants an easy, automated way to add cross-mod integrations. Instead of hardcoding compat logic or…
Official listing
- Modrinth page
- modrinth.com/mod/compat-api
- Owner
- FixerLink
- Published
- 2025-11-27
- Updated on Modrinth
- 2026-03-20
- Facts verified
- 2026-10-15