modde

A cross-platform game mod manager written in Rust, running natively on Linux, macOS, and Windows. Provides mod management with virtual filesystem deployment, profile management, save versioning, and conflict detection.

Project site: https://modde.rs/ Documentation: https://modde.rs/docs/

Supported games

Fifteen titles ship across the Creation Engine, Gamebryo, REDengine, Unreal 4/5, Larian, SMAPI, and Bannerlord engines; additional titles can be added at runtime as user-defined games. Games are auto-detected via Steam (Proton) and Heroic (GOG, Epic, sideload) launchers. The canonical status baseline for these claims lives in docs/capability-matrix.toml.

Features

• Virtual filesystem deployment: Symlink farm keeps the game directory clean and unmodified; atomic rollback to previous deployments
• Wabbajack on Linux: Native parsing of .wabbajack modlist archives without a Windows VM
• Profile management: Create, fork, switch, and delete profiles; stackable experiments with rollback (like git branches); load order locking
• Save management: Git-backed save vaults with SHA-256 fingerprinting, compatibility warnings, and auto-capture for games with real save tracker support
• Conflict detection: Graph-based collision analysis with classification (dangerous vs cosmetic) and resolution suggestions
• Nexus-first installs: Nexus Mods API (REST + GraphQL browse/search), nxm://, Browse Nexus, Wabbajack modlists, and Nexus Collections are the primary shipped install flows
• Additional download backends: GitHub, Direct, Google Drive, MEGA, and MediaFire backends exist today mainly for Wabbajack/directive installs
• Installers: FOMOD is shipped end to end (interactive wizard plus declarative TOML/JSON/Nix configs); BAIN detection/execution exists but still requires the user-input selection flow
• Gaming tools & executables: MangoHud, vkBasalt, GameMode, ReShade, OptiScaler, and Proton are configured and patched from both the CLI and UI; named external executables (xEdit, BodySlide, Nemesis, …) run with overwrite capture via modde exec / modde tool add-executable
• Diagnostics: CLI and UI diagnostics use real plugin order plus resolved conflicts instead of placeholder inputs
• Reachable advanced views: Downloads, Data Files, Diagnostics, Tools, and Executables are connected in the UI; some remain Partial rather than MO2-complete (see parity audit)

Architecture

Usage

# Detect installed games
modde detect

# Install a Wabbajack modlist
modde install wabbajack /path/to/modlist.wabbajack \
  --profile my-skyrim \
  --game-dir "/home/me/.local/share/Steam/steamapps/common/Skyrim Special Edition"

# Deploy mods and play
modde play my-skyrim --game skyrim-se

# Manage profiles
modde profile fork my-skyrim experimental-build --game skyrim-se
modde profile try experimental-build --game skyrim-se   # start experiment
modde profile rollback experimental-build --game skyrim-se  # revert

# Manage saves
modde save capture --game skyrim-se --profile my-skyrim
modde save history --game skyrim-se --profile my-skyrim
modde save watch --game skyrim-se  # auto-capture on changes

# Analyze conflicts
modde collisions --profile my-skyrim --game skyrim-se

# Check for updates
modde update check --profile my-skyrim --game skyrim-se --period 1w

# Launch the GUI
modde gui

Installation

Every release ships two binaries: the modde command-line tool and the modde-ui desktop app. Install them through your platform's native package manager, a direct download, Cargo, build from source, or — if you use Nix — a flake with a declarative home-manager module. There is no single blessed method; pick whatever fits how you already manage software. The canonical, exhaustive list lives in the installation guide.

Linux

# Arch (AUR) — modde-bin (prebuilt), modde (source), or modde-git (dev branch)
yay -S modde-bin

# Fedora / RHEL (COPR)
sudo dnf copr enable caniko/rs-modde
sudo dnf install modde modde-ui

# Debian / Ubuntu (apt)
sudo install -d -m 0755 /etc/apt/keyrings
curl -fsSL https://modde.rs/apt/key.gpg.asc | sudo gpg --dearmor -o /etc/apt/keyrings/modde.gpg
echo "deb [signed-by=/etc/apt/keyrings/modde.gpg] https://modde.rs/apt/ stable main" \
  | sudo tee /etc/apt/sources.list.d/modde.list
sudo apt update && sudo apt install modde modde-ui

# Flatpak (GUI)
flatpak install flathub com.tartanoglu.modde

# AppImage (self-contained) or tarball from the releases page
chmod +x modde-ui-<version>-x86_64.AppImage && ./modde-ui-<version>-x86_64.AppImage

macOS

brew tap caniko/modde https://codeberg.org/caniko/homebrew-modde
brew install modde

The formula installs both modde and modde-ui on Apple Silicon and Intel Macs. To install from a downloaded tarball instead, clear the macOS quarantine attribute once after extracting, then run normally:

tar xzf modde-<version>-aarch64-darwin.tar.gz   # or x86_64-darwin on Intel
xattr -dr com.apple.quarantine modde modde-ui
./modde --help

modde ships ad-hoc-signed macOS binaries (no Apple Developer ID, no notarization). The xattr -dr step removes the "downloaded from the internet" flag that triggers Gatekeeper; subsequent runs work without further intervention. If you'd rather have notarized binaries (Apple Developer ID, $99/yr), open an issue to fund or contribute it.

Windows

winget install Caniko.Modde      # or: scoop install modde / choco install modde

Each Windows package installs modde.exe and modde-ui.exe on your PATH. To install from the downloaded .zip instead, verify the Authenticode signature before running:

Get-AuthenticodeSignature .\modde.exe
Get-AuthenticodeSignature .\modde-ui.exe

Both should report Status : Valid. On Linux you can verify the same files with osslsigncode verify -in modde.exe.

Cargo

cargo install modde-cli

This builds the modde CLI from source (the GUI lives in a separate crate not published to crates.io). It requires a Rust 2024 edition toolchain plus SQLite and OpenSSL development headers — openssl-sys will not build without OpenSSL. See the installation guide for the per-distro package lists.

From source

git clone https://codeberg.org/caniko/rs-modde.git
cd rs-modde
nix develop . -c cargo build --release
# Binaries at target/release/modde and target/release/modde-ui

Use nix develop . -c cargo test --workspace for authoritative validation. A plain cargo test --workspace outside the Nix shell is not a reliable signal because openssl-sys will fail to locate OpenSSL on an unprepared host.

Nix

If you use Nix, modde is also a flake — a reproducible install that, through the home-manager module, additionally lets you declare your mod profiles as code. It's one option among many, not required and not "the" way in.

# Run directly
nix run codeberg:caniko/rs-modde#modde

# Install to profile (both modde and modde-ui)
nix profile install codeberg:caniko/rs-modde#modde

# Development shell
nix develop codeberg:caniko/rs-modde

To wire the flake into your own config and declare profiles, add it as a flake input and import the home-manager module (see Home-Manager Module below):

# In your flake.nix inputs:
inputs.modde.url = "codeberg:caniko/rs-modde";

Privacy

Telemetry

modde has a remote-telemetry Cargo feature in modde-cli. It is opt-in (off by default in published builds) and currently a no-op stub - the feature compiles a detritus client, but no live endpoint is configured. Nothing is sent anywhere today.

When/if a telemetry backend is stood up, this README and the CHANGELOG will document:

• exactly what is collected,
• the opt-in flag,
• the endpoint URL,
• the data retention policy.

Until then: assume modde sends nothing. If you want to confirm, cargo tree -e features will show whether remote-telemetry is active in your build (it isn't, unless you explicitly enabled it).

Home-Manager Module

For Nix users, a home-manager module is included as the declarative option: configure your mod profiles as code and have them deploy on activation.

{
  programs.modde = {
    enable = true;
    profiles = {
      my-skyrim = {
        game = "skyrim-se";
        installMode = "auto";
        gameDir = "/home/me/.local/share/Steam/steamapps/common/Skyrim Special Edition";
        wabbajackList = {
          url = "https://example.com/modlist.wabbajack";
          hash = "sha256-...";
        };
      };
      my-local-skyrim = {
        game = "skyrim-se";
        gameDir = "/home/me/.local/share/Steam/steamapps/common/Skyrim Special Edition";
        wabbajackList = {
          path = /nix/store/...-Legends-of-the-Frost.wabbajack;
        };
      };
      my-cyberpunk = {
        game = "cyberpunk2077";
        nexusCollection = {
          slug = "my-collection";
          version = "1";
        };
      };
    };
  };
}

Set installMode = "await-game" while the game is not installed yet. modde waits for Steam/Heroic-managed game installs and does not install the base game itself.

Add the module to your home-manager imports from the flake:

# In your flake.nix inputs:
inputs.modde.url = "codeberg:caniko/rs-modde";

# In your home-manager config:
imports = [ inputs.modde.homeManagerModules.modde ];

Platform Support

modde runs natively on all three desktop platforms; every one is first-class.

CI

Forgejo Actions on Codeberg runs cargo fmt --check, cargo clippy, coverage tests, Rust release builds, Nix package builds, and nix flake check on every push and pull request. Pushes to trunk also build and deploy the documentation site and presentation website to Codeberg Pages.

Tag releases are managed through cargo xtask release. Run cargo xtask release X.Y.Z --dry-run to preview a workspace release, then cargo xtask release X.Y.Z to publish all workspace crates to crates.io and push the bare X.Y.Z tag. Release tags build and publish Linux, macOS, and Windows CLI/GUI artifacts.

Website and docs

The presentation site (website/) is a Zola static site; the documentation (docs/) is an mdBook. The combined site output places the website at the root and the docs under /docs/.

nix build .#website
nix build .#docs
nix build .#site

For local editing:

cd website && zola serve   # presentation site
cd docs && mdbook serve     # documentation

Contributing

See CONTRIBUTING.md for development setup and guidelines.

Security

See SECURITY.md for the security policy.

License

GPL-3.0-only