Rai Pal: a mod manager for universal game mods, and how it guesses what you own

Universal mods are the whole point of the app

Rai Pal describes itself as a tool that helps you use and make universal game mods, and that means mods which are not made for any specific game but work across multiple games, usually of the same game engine. The README names UEVR and UUVR as the popular examples. That category is where the value lies, because a universal mod needs to know which game it is attaching to and which engine version that game uses, and getting either wrong tends to mean a black screen. The listed features follow directly from that. Rai Pal auto-finds installed games from supported providers, auto-finds owned games that are not necessarily installed, detects information about each game such as the game engine and engine version, and then installs, runs and updates the correct version of a universal mod. The audience is a player with a large library across several stores rather than a mod author looking for a build pipeline.

Finding games without logging into every store

The mechanism for discovery is file analysis rather than API calls, and the README is candid about the reason. Rai Pal analyzes files on your system to determine which games you own and which are currently installed, and there is guesswork involved, especially because the app tries to give you this information as quickly as possible without the need to log in with each provider's account. Steam detection also picks up non-Steam games added to the Steam library. GOG and Epic detection work for both installed and owned games. Itch detection works for both too, but the owned list does not include games from bundles unless you add them to your library, and the README links to scripts for pulling all bundle games into the library while noting they are slow and not recommended by the Itch team. PC Xbox is the outlier: installed games are found only when marked as moddable, meaning those whose files folder you can open through the Xbox app, and owned games are not available at all. For every other provider, the README says you add games manually with the add game button on the installed games tab or by dropping the game exe on the Rai Pal window.

Engine detection is graded, and the grades get worse for owned games

This is the part of the project most worth reading closely, because the README publishes its own confidence levels rather than claiming a certainty it does not have. For installed games, detection is usually straightforward: Steam, GOG, Epic and Itch all report both engine and engine version, while PC Xbox reports the engine but only Unity for the version. For owned games, detection uses remote sources and often goes by the game's name, and the confidence drops accordingly. Steam gets a great guess for the engine and a good guess for the version, GOG gets a good guess for both, Epic and Itch get a decent guess for both, and PC Xbox offers nothing at all. A table of grades in the documentation is unusual and useful. It tells you that the engine information shown for a game you own but have not installed is a name-based guess, and that a mod chosen on the strength of such a guess is a candidate rather than a match.

Installing on Windows and Linux

Two platforms are covered, each with a direct download and, on Windows, a package manager route. On Windows the README points at an installer download, and the winget command is given as:

winget install Raicuparta.RaiPal

On Linux the distribution is an AppImage, downloaded from the releases page. The script name in the winget identifier, Raicuparta.RaiPal, follows the publisher.package convention rather than the repository name, which is worth noting if you script the install across machines. The rest of the workflow is the app itself: pick a game, pick a mod, and let the app install or run it. Because the app is a desktop program rather than a library, there is no configuration file to write and no service to register, and the version you get is the version in the latest release. Releases are tagged as v0.24.0 on 2026-10-17, v0.23.0 on 2026-10-06 and v0.22.0 on 2026-09-13, and the last push to the repository was on 2026-10-19, so the project is shipping frequently on a pre-1.0 version line.

The rai-pal:// scheme lets other tools drive the app

Rai Pal registers the rai-pal:// URL scheme, also known as protocol urls, and the README documents four of them. The add-mod-source link asks the user to add a custom mod database, which is the same as pasting a URL into the mod sources dialog. The install-mod, uninstall-mod and run-mod links take a providerId, a gameId and a modId and respectively install a mod for a game, uninstall a mod from a game, or run a game with a mod. The identifiers are not guessable, and the README says how to find them: check the Debug Data buttons in Rai Pal, which are available in the games tab when a game is selected and in the mods tab when a mod is selected. This is the piece that lets a launcher, a script or a second tool drive installs and launches without a full user interface, and it also means a link in a chat or a browser can trigger an install prompt in the app.

A Tauri desktop app with a Rust backend and a TypeScript frontend

The repository layout explains the engineering choices. The primary language is Rust and the tree holds a backend directory alongside a frontend directory, with package.json, vite.config.ts, tsconfig files and eslint configuration at the root, plus index.html and public assets for the web side. The npm scripts confirm the stack: dev runs tauri dev, build runs tauri build, frontend:build runs tsc and then vite build, and lint runs eslint with a fix pass and then cargo clippy with a fix pass in the backend directory. There is a Containerfile.linux and a Containerfile.windows for reproducible builds, and the podman-build scripts run npm run build inside builder images published to ghcr.io. A flake.nix and flake.lock show that Nix is used for the toolchain, and an AGENTS.md plus a .agents directory point to machine-readable contributor instructions. A deploy-deck script copies the built AppImage to a device over scp and sets it executable, which tells you the author builds for a Steam Deck-style Linux target as well as for desktop.

GPL-3.0 and the practical limits of the current release

Rai Pal is released under the GNU General Public License version 3 or later, and the README reproduces the standard notice with the copyright line for 2024 Raicuparta. For a desktop tool that users download rather than embed in a product, that is a reasonable choice, and it does mean anyone redistributing a modified build has to keep the same licence terms. The licence text in the README is cut off partway through the standard notice, so the repository's LICENSE file is the authoritative copy. On the feature side, the limits are concrete rather than philosophical. There is no support for games from providers outside the five listed, the owned-games view is missing entirely for PC Xbox, and the engine detection for owned games rests on names and remote sources. The project is still on version 0.x with a release roughly every ten days, which for a mod manager means interface and behaviour can shift between versions and that a mod compatibility change may arrive ahead of a manager update.

Editorial conclusion

Rai Pal fits a player who uses universal mods such as UEVR or UUVR across several Unity or Unreal titles and wants one place that knows which games are installed, which engine version each one uses, and which mod build applies. It is the wrong tool for a game that has no universal mod, and it is the wrong tool if you need certainty rather than a guess, because for owned but uninstalled games the engine detection degrades to a name-based lookup that the project itself grades from great guess down to not available. Verify first how Rai Pal sees your library by opening the games tab and reading the Debug Data buttons before you install anything, since the same buttons expose the providerId, gameId and modId values that the rai-pal:// links need, and confirm that the game you care about is detected as installed rather than merely owned.

Frequently asked questions

Official sources

1. License: GPL-3.0
2. Project website
3. Raicuparta/rai-pal on GitHub
4. README
5. Releases