Packweaver

A desktop modpack builder for Minecraft — create, customize, and export modpacks from multiple sources.

Packweaver is a Tauri app (Rust + React + TypeScript) that lets you build Minecraft modpacks by picking a base pack from Modrinth or a local file, layering in your own custom mods, and exporting a client .zip. It is a builder/exporter, not a launcher — play stays in tools like Prism; a future “install into …” exporter is optional and far out.

Platform: Windows only (other OS targets are not supported or tested).

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What it does

1. Create an Instance — pick a base modpack from Modrinth or a local .mrpack/.zip. Packweaver installs it into workspace/client/{stem}/ (Minecraft-shaped, not a raw archive dump).
2. Customize — add custom mods; toggle base or custom mods on/off (off = jar removed from that side’s tree).
3. Rebuild — wipe workspace/client/, reinstall the base pack under {stem}/, re-layer enabled customs (repairs messy instances).
4. Export — zip workspace/client/{stem}/ as {stem}-MODIFIED.zip. With Server Pack Packager enabled: rebuild workspace/server/{stem}/ and export -MODIFIED-server.zip.

.mrpack exporter is not available yet.

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Pipeline

flowchart LR
    A([Pick Source<br/>Modrinth · Local]) --> B[Fetch to original/]
    B --> C[Install into workspace/client/stem]
    C --> D{Customize}
    D -->|Toggle / add| D
    D --> E[Rebuild or Layer]
    E --> F([Export -MODIFIED.zip])

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Per-instance layout:

instances/{id}/
  original/{realFilename}.mrpack
  workspace/
    client/{stem}/        # client — enabled content only
      mods/
      config/
      ...
    server/{stem}/        # server — when Server Pack Packager plugin is on
      mods/
      ...

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Tech stack

Layer	Tech
Desktop shell	Tauri v2
Backend	Rust
Frontend	React 19 + TypeScript + Vite
Database	SQLite via rusqlite
HTTP	reqwest (async)
Modpack sources	Modrinth API, local files

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Project structure

public/                 # Static assets (README screenshot, plugin icons)
src/                    # React frontend
  components/           # UI components
  plugins/              # Source + exporter plugins
    modrinth.ts         # Modrinth search & version fetching
    exporters/          # mrpack, zip, server exporters
  types/                # Shared TypeScript types

src-tauri/              # Rust backend
  src/
    lib.rs              # Tauri commands
    downloader.rs       # Install/rebuild + custom layer + zip
    installer.rs        # mrpack → Minecraft-shaped workspace
    fetchers.rs         # BasePackFetcher trait (Modrinth, Local)
    db.rs               # SQLite init & additive column upgrades
    models.rs           # Rust structs
    jar_inspector.rs    # Reads mod metadata from .jar / .zip

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Getting started

Prerequisites: Rust, Node.js, pnpm

# Install dependencies
pnpm install

# Run in development
pnpm tauri dev

# Build for production
pnpm tauri build

Scripts

Command	Does
pnpm test	Frontend (vitest) + Rust (cargo test) tests
pnpm check	Format/lint/typecheck (frontend + Rust) then pnpm test
pnpm fix	Auto-format/lint-fix frontend + cargo fmt
pnpm update	Bump pnpm + cargo deps, then pnpm test
pnpm build:zip:win	tauri build + zip the release .exe

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Domain model

Term	Meaning
Instance	A workspace built on top of a Base Pack
Base Pack	The modpack used as the foundation (e.g. a Modrinth pack)
Platform Source	Where the Base Pack comes from (Modrinth, local)
Base Mod	A mod inherited from the Base Pack
Custom Mod	A mod added manually by the user on top of the Base Pack
Enabled	Whether a mod is included in the exported output