The repository simonw/browser-compat-db contains a conversion of Mozilla’s mdn/browser-compat-data into a SQLite database that is published on GitHub with open CORS headers. The resulting SQLite file is approximately 66 MB in size.
What was done and how
- Parts of the conversion script were generated by Claude Code for web (Opus 4.8).
- The conversion and database construction used the sqlite-utils tool.
- To serve the final ~66MB SQLite file via the GitHub CDN with open CORS headers, the author built a GitHub Actions workflow that compiles the database and then force-pushes it to an orphan branch named "db".
Why a special publishing approach?
GitHub Releases do not generally provide files with open CORS headers, while files stored in a normal GitHub repository can be served with those headers. To exploit that, the workflow pushes the built database into a regular branch (an orphan "db" branch), allowing the file to be served by the GitHub CDN with open CORS so it can be fetched from browsers.
How the published database can be used
The published SQLite database is available for download from the repository. Because it is hosted with open CORS headers, it can also be explored directly from a browser — for example using Datasette Lite for interactive inspection.
Tools and components
- Source compatibility data: mdn/browser-compat-data (maintained by Mozilla)
- Conversion repository: simonw/browser-compat-db
- Script generator: Claude Code for web (Opus 4.8)
- Database tooling: sqlite-utils
- CI/workflow assistance: Codex Desktop (GPT-5.5) helped create the GitHub Actions workflow
- Publishing method: force-push the built SQLite file to a "db" orphan branch so it is served via the GitHub CDN with open CORS
This setup is intended for developers and researchers who want convenient, browser-accessible SQLite access to MDN’s compatibility data.
