# Modkeel

> Modkeel keeps modded Minecraft steady. The Modkeel Companion is a free, open source (MIT) mod for Fabric, NeoForge and Forge that backs up worlds when the mods change, names the mod that most likely crashed the game, and offers a one-click fix (turn that mod off, or go back to the mods that last worked). It has no mixins, so it cannot be what breaks a pack, and it sends nothing unless the player chooses to share.

- Supported: Fabric on Minecraft 1.20.1, 1.21.1, 1.21.11 and 26.x; NeoForge on 1.21.1; Forge on 1.20.1.
- Download: [GitHub releases](https://github.com/Modkeel/companion/releases/latest) (jars built by CI with provenance and VirusTotal scans). Modrinth and CurseForge listings are in review.
- Not an official Minecraft product; not affiliated with Mojang or Microsoft.

## Crash help

- [Find which mod crashed Minecraft](https://modkeel.com/crashes/which-mod-crashed): where the crash report is, which lines name the mod, narrowing it down by halves, and the Companion naming it on the next start.
- [Update a modpack without losing your world](https://modkeel.com/guides/update-modpack): copy the world, swap each mod for a release made for the new version, keep a way back; lab counts of older releases that did not start.
- [Crash helper mods compared](https://modkeel.com/guides/crash-mods-compared): Modkeel Companion, Crash Assistant, Not Enough Crashes, Neruina and CrashPatch; which names the mod, turns it off, keeps the game open or protects worlds.
- [Crash report reader](https://modkeel.com/crashes/diagnose): paste a crash report (starts with `---- Minecraft Crash Report ----`) or latest.log, get the mod that most likely caused it, the kind of crash and the fix. Nothing is stored.
- [Why did my modded Minecraft crash?](https://modkeel.com/crashes/): the four common crash errors and how to read a crash report.
- [Mixin apply failed](https://modkeel.com/crashes/mixin-apply-failed): MixinTransformerError, InvalidInjectionException; mod for another Minecraft version or two mods patching the same code.
- [NoClassDefFoundError, NoSuchMethodError, ClassNotFoundException](https://modkeel.com/crashes/noclassdeffounderror): missing library mod or version mismatch.
- [Mod loading failed](https://modkeel.com/crashes/mod-loading-failed): "Incompatible mods found!" (Fabric), "Mod loading has failed" (NeoForge, Forge); missing, wrong, duplicate or wrong-loader mods.
- [OutOfMemoryError: Java heap space](https://modkeel.com/crashes/out-of-memory): how much RAM to give modded Minecraft and where to set it.

## Lab data

- [Mods tested by Minecraft version](https://modkeel.com/minecraft/): which mod releases ran on each Minecraft version in the Modkeel lab, which ran together, and which releases made for older versions did not start.
- [Minecraft 26.3](https://modkeel.com/minecraft/26-3), [26.2](https://modkeel.com/minecraft/26-2), [1.21.11](https://modkeel.com/minecraft/1-21-11), [1.21.1](https://modkeel.com/minecraft/1-21-1), [1.20.1](https://modkeel.com/minecraft/1-20-1).
- Per mod: which releases ran on which Minecraft version and the mods each ran with, at https://modkeel.com/mods/{mod_id}, e.g. [Sodium](https://modkeel.com/mods/sodium), [Lithium](https://modkeel.com/mods/lithium), [Iris Shaders](https://modkeel.com/mods/iris).

## Data API

Read-only JSON at https://api.modkeel.com, no key, open to any origin. Data: what the Modkeel lab saw mods do (CC BY 4.0, attribute "Modkeel lab data (modkeel.com)"). Mods are named by mod id (e.g. sodium, lithium); `mc` is an optional Minecraft version filter.

- [GET /v1](https://api.modkeel.com/v1): the list of endpoints.
- [GET /v1/mods/{mod_id}?mc=](https://api.modkeel.com/v1/mods/sodium): the lab runs of a mod and the mods it ran with or clashed with.
- [GET /v1/pairs/{mod_id}/{mod_id}?mc=](https://api.modkeel.com/v1/pairs/lithium/c2me): `ran_together`, `clash` or `untested`.
- POST https://api.modkeel.com/v1/diagnose with a crash report or latest.log as the text body: kind, confidence, suspect mods with reasons, Minecraft version, loader, and a guide link. The text is not stored.
- [MCP server](https://modkeel.com/mcp) at https://api.modkeel.com/mcp (Streamable HTTP, no key; also on Smithery: https://smithery.ai/servers/modkeel/modkeel): tools `diagnose_crash`, `mod_lab_runs` and `mod_pair`, for AI assistants.

## Project

- [Privacy](https://modkeel.com/privacy): what the Companion sends, only when the player shares, and how to have it deleted.
- [Companion source](https://github.com/Modkeel/companion)
- [Modkeel CLI](https://github.com/Modkeel/modkeel): finds, builds and verifies community ports of mods for Minecraft versions their authors have not updated to yet.