Specly
Context
Teams were writing OpenAPI files by hand in YAML, then building Postman test cases and mock servers separately. Specly lets you design an API from sample JSON and get the spec, the test cases and a working mock from one place.
I built it mostly on my own, with a few early contributions from another developer. I handled the product design, the spec engine, the Nuxt app, the Supabase data model and billing.
What I did
Each project stores one real OpenAPI document. Endpoints and schemas are inferred from sample JSON, and test cases live inside the spec as an extension. Because of that, an export can be imported back with nothing lost, and the user is never locked in.
Every edit is a small change sent along with the spec revision it was based on. If two collaborators edit the same project, the second save gets a 409 conflict, so it can never silently overwrite the first.
The hosted mock server checks each request against the spec before it answers with generated data. That way a client hitting the mock gets the same 400s it would get from the real API.