I am a backend developer. Every time I start an Express project I need API docs (like swagger of fastAPI but in express). I look up the options and every single one has a dealbreaker. swagger-jsdoc wants YAML in comments above every route. swagger-autogen misses dynamic routes. express-oas-generator starts completely empty, the UI only populates after you've manually hit every endpoint. swagger-ui-express doesn't even generate anything, you bring your own complete spec file. Meanwhile FastAPI just works. Start the server, open /docs, everything is there. Zero annotations, zero config. No need for developer to write anything.
The weird part is the information already exists in any Express app. app._router.stack holds every registered route at startup before any request is made. And if you're using Zod or Joi for validation which most serious apps do those schemas are rich runtime objects with field names, types, and constraints already. So in theory something could read the route table, detect your existing validators, combine both, and serve a live docs UI with zero annotations. Because it feels like a solved problem that somehow isn't solved yet.
So I built it. I felt pain and no solution existed. No annotation, no docs, no major changes in code