About

About Modkeel

Modkeel is free, open source (MIT) tooling for modded Minecraft. It is built and run by Juan Zabala, an independent developer.

What Modkeel makes

The Modkeel Companion, a mod for Fabric, NeoForge and Forge. It copies each world before it loads with different mods; after a crash, the next start names the mod that most likely caused it and offers to turn it off, or to go back to the mods that last worked.
The Modkeel app for Windows, macOS and Linux. Name a mod and your Minecraft version: it looks for the author's build, an older build that still runs there, or a community port, checks each one before you get it, and can move a whole pack to another version as a new instance beside the old one.
The Modkeel CLI, the same engine on the command line, on PyPI as modkeel.
An MCP server at https://api.modkeel.com/mcp, so AI assistants can read a crash or look up a mod with the lab's data: how to add it.
Community ports: builds of mods for Minecraft versions their authors have not released for yet, made from each mod's own source on GitHub Actions.

Real games. Mods are started in real Minecraft clients and servers, and the lab records what happened: a world loaded, a server finished starting, or the game stopped. A port is listed only after it ran in a modpack on a real server and client.
Bytecode linkage checks. Before a JAR built for one Minecraft version is offered for another, its bytecode is checked against the target version: the classes, methods and fields it calls must exist there, and its mixins must still find their targets.
JAR safety scans. Every JAR is scanned before the lab starts a game with it, for known malware, webhooks, code that reads login files and sends data out, and code that runs other programs or downloads more code.
Readiness data. Every day the lab asks Modrinth which of the most downloaded mods have a release build for the newest Minecraft versions, and publishes the counts on the version pages.
Benchmarks. Frame rate and server timings with each mod against the same game without mods; how they are measured, with the raw data.

Lab data is published under CC BY 4.0: see mods and Minecraft versions.