protONsteam 🐧

A cross-browser extension that shows ProtonDB compatibility ratings directly on Steam game pages — right next to the game title, no tab switching needed.

Disclaimer: protONsteam is an unofficial community project. It is not affiliated with, endorsed by, or connected to ProtonDB, Valve, or Steam in any way. It uses ProtonDB's public API which is unofficial and may change at any time.

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Ratings

Tier	Meaning
🐧 Native	Has a native Linux build
🏆 Platinum	Works perfectly out of the box via Proton
🥇 Gold	Works great with minor tweaks
🥈 Silver	Works with some issues
🥉 Bronze	Runs but expect significant problems
💀 Borked	Does not run at all
❓ Not Rated	No reports on ProtonDB yet

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Installation

Firefox (recommended)

Install directly from the Firefox Add-ons store:

→ Install on Firefox Add-ons

Chrome / Chromium / Edge

1. Go to chrome://extensions/
2. Enable Developer mode (top right toggle)
3. Click Load unpacked
4. Select the protONsteam/ folder

Manual Firefox install (developer)

1. Go to about:debugging#/runtime/this-firefox
2. Click Load Temporary Add-on…
3. Select manifest.json inside the project folder

Temporary add-ons are removed when Firefox closes. Use the AMO link above for a permanent install.

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How it works

1. When you visit a Steam game page (store.steampowered.com/app/{appId}/...), the content script extracts the App ID from the URL.
2. It sends a message to the background script, which fetches the rating from the ProtonDB public API:

   https://www.protondb.com/api/v1/reports/summaries/{appId}.json
   

3. A styled badge is injected inline next to the game title showing the tier.
4. Clicking the badge opens the game's full ProtonDB page in a new tab.

Permissions used

Permission	Why
store.steampowered.com	To inject the badge on Steam game pages
www.protondb.com	To fetch the compatibility rating

No data is collected, stored, or transmitted beyond these two requests.

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Project structure

protONsteam/
├── manifest.json    # Extension manifest (MV3, cross-browser)
├── background.js    # Background script — handles ProtonDB API fetch
├── content.js       # Injected into Steam pages — renders the badge
├── styles.css       # Badge styles
├── icons/           # Extension icons (16, 48, 128px)
└── README.md

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Contributing

PRs are welcome! Some ideas for future improvements:

• Show the number of reports alongside the tier
• Add a confidence score indicator
• Support Steam search/browse pages (inline badges per game)
• Option to disable the badge on specific games

To contribute:

1. Fork the repo
2. Create a branch (git checkout -b feat/my-feature)
3. Commit your changes (git commit -m 'feat: add my feature')
4. Push and open a Pull Request

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License

MIT — see LICENSE for details.