MRPack to ZIP

What Is a .mrpack File? Modrinth's Modpack Format Explained

The short answer

A .mrpack file is a ZIP archive that follows Modrinth's modpack specification. Its purpose is to describe a complete Minecraft modpack without including the mod files themselves — instead it lists URLs from which each mod should be downloaded.

Inside a .mrpack file

If you change the extension to .zip and extract, you find:

my-modpack.mrpack
├── modrinth.index.json    ← the manifest
└── overrides/             ← optional folder
    ├── config/
    ├── resourcepacks/
    └── scripts/

The modrinth.index.json manifest

A JSON document listing every mod with its file size, SHA-512 hash, and one or more download URLs. The launcher reads this manifest, fetches each URL, and assembles the playable modpack on disk. See field-by-field reference.

The /overrides folder

Files that should be copied into the Minecraft instance as-is: configuration files, scripts, resource packs, shaders, and anything else not available as a mod download. These are the modpack author's customizations.

Why .mrpack is a "shopping list," not a "shopping bag"

Because the mods are referenced rather than included, .mrpack files are tiny — usually 10–500 KB even for packs with hundreds of mods. This is good for sharing and bad for offline use: without an internet connection, a .mrpack cannot turn into a playable modpack on its own.

How .mrpack differs from CurseForge ZIP modpacks

CurseForge's ZIP modpacks include a manifest.json listing projectID/fileID pairs from CurseForge's own API. Modrinth's .mrpack lists direct URLs and hashes. The trade-off: Modrinth's format is launcher-agnostic; CurseForge's is tightly coupled to CurseForge.

Full comparison: modpack formats compared.

When you should convert to ZIP

  • You want to use the modpack in a launcher that does not read .mrpack (CurseForge desktop, vanilla launcher)
  • You want to upload the pack to a server host that only accepts ZIP
  • You want to share with someone who is offline and cannot download mods themselves

For all three, head to our main converter.