Swimm
swimm.ioDocumentation
Docs that live next to your code and flag themselves as stale in CI when the code moves on without them.
Other products from Documentation
If your product is an API, this turns your OpenAPI spec into docs devs can actually test requests against.
Point it at a GitHub repo and get a polished, AI-searchable docs site without touching a CSS file.
The default pick when you want docs that read like a real product, not a wall of Markdown.
Free, open-source, and battle-tested by half of GitHub's OSS projects — the safe default for docs-as-code.