Modpack Formats Compared: .mrpack vs CurseForge .zip vs MultiMC Instance
Three formats, three philosophies
| .mrpack (Modrinth) | CurseForge .zip | MultiMC instance | |
|---|---|---|---|
| Manifest file | modrinth.index.json | manifest.json | instance.cfg + mmc-pack.json |
| Mod references | Direct URLs + hashes | CurseForge projectID + fileID | Local JARs in .minecraft/mods |
| Service dependency | Modrinth (or any mirror) | CurseForge API | None |
| Portability | High | Locked to CurseForge ecosystem | Highest (self-contained) |
| File size | Tiny | Tiny | Full |
What this means in practice
If you publish on Modrinth, your audience can play across any compatible launcher. If you publish on CurseForge, your audience needs the CurseForge ecosystem. A "MultiMC instance" ZIP is the most portable for offline sharing because it contains everything.
Our converter unifies these: it takes a .mrpack and produces a fully-resolved ZIP that behaves like a self-contained instance.