# Adding Routes

New API routes go in their own module under `shelfmark/core/`, named for the group (`stats_routes.py`, `settings_routes.py`), as a `register_<group>_routes(app, ...)` function that `main.py` calls once. Anything the routes need that lives in `main.py` or is shared with another group, such as `login_required`, the auth mode or the user database, is passed in as a parameter, so a route module never imports `main`. When a test patches one of those, pass a callable that is evaluated per request, the way `register_stats_routes` does. Helpers that belong to one group stay in its module. Please don't add `@app.route` handlers to `main.py` itself: two PRs that each add a route there land in the same stretch of the file and conflict, where two route modules only share the one register call. `shelfmark/core/stats_routes.py` is the smallest example to copy. A few older routes are still in `main.py` and are being moved out one group at a time, see [Discussion #1536](https://github.com/calibrain/shelfmark/discussions/1536).