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openstreetmap/openstreetmap-website
The Rails application that powers OpenStreetMap
This is the Rails application behind openstreetmap.org, covering user accounts, diaries, messaging, the v0.6 editing API, the Browse pages and GPX uploads. It suits developers who want to study or contribute to a large Rails codebase that serves real production traffic, or who are considering running their own OSM-style instance.
The repo is pushed to actively and runs lint and test workflows on master, so the contribution bar is enforced by CI rather than by reviewer memory. Permissions for the web UI and the API live in separate ability classes, which keeps API-specific rules out of browser code paths. UI translation goes through Translatewiki, so contributors are not hand-maintaining locale files across dozens of languages. A devcontainer and a Dockerfile are included, which shortens the path to a running environment compared with installing everything by hand.
Setup is the real cost. The README sends you to INSTALL.md for a full installation, and a working instance depends on tile and geocoding services that the default configuration borrows from public providers, so a fully private deployment means standing up more infrastructure yourself. This is a single-site application rather than a framework, and OSM-specific behaviour such as changeset rules and the semantics of the editing API is built in throughout, so forking it for a different product means removing a lot first. The licence is GPL-2.0, so anything you distribute that builds on it has to be GPL-2.0 too, which rules out most closed-source reuse. The README lists three maintainers, which is a thin group for a site of this size.