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Show HN: OpenAPI mocks that don't suck – realistic test data, quick setup

13 points - 07/08/2025


Hi HN!

I'm Ankit, the founder of Beeceptor, a request mocking and intercepting tool. This time, I built something new to address a pain I’ve personally felt (and heard from dozens of QA, frontend, and platform teams): making OpenAPI specs actually useful during development.

API contracts just sit around as docs often. What if you could 'activate' them, instantly have a realistic, hosted mock server-with contract validation, smart test data, and early usage?

So I made _Mockaroo for OpenAPI_, but with brains. It spins up a hosted mock server from your spec in one click. It:

- Generates sensible context-aware, test data using FakerJS (e.g., age returns realistic numbers, not 10000)

- Validates incoming requests against your contract definition and returns detailed, actionable error messages.

- Supports JSON, binary, CRUD style API responses.

- Gives a HOSTed API server URL, that's ready in a few seconds.

- Helps frontend teams start testing before the backend is ready - Gives QAs a place to play, verify and run performance tests. - Enables the best developer experience, requiring no account setup and a working mock API server for experiments, and API cost savings.

No local setup, no writing custom mock rules, no fuss. Just activate your OpenAPI spec, and your API starts “working” in seconds.

Besides, Beeceptor shows live request logs, where responses can be overridden.

Quick demo: https://www.youtube.com/watch?v=2vUD_B3aw5I ---

Would love your thoughts, feedback, or use cases I haven’t thought of yet. Happy to share more technical details if there's interest.

Thanks for reading!

Source

  • anitil

    07/09/2025

    This is really cool. I was initially skeptical about the 'AI' pitch on your page but having played with it I think that should be your number one pitch, particularly on HN.

    For people reading: Using FakerJS and any Yaml/Json library it'd be "easy" to mock things like String or Object, but (if I understand correctly) this goes much further and looks at the name of the entry and something something ai and gives you a realistic response.

    So a string called 'username' returns a valid name, which is already handy, but it also matches the 'email' field, which is even better. And the name even matches the country (I got an Italian-seeming name with an address in Italy)

    I'm impressed, I'll be sharing this with people at work.

      • ankit84

        07/09/2025

        Great to see your usage @anitil. These aren't just static dummy mocks. Beeceptor looks at schema, fields, description, format, datatypes, and then generats a realistic mock responses to match real response.

    • gadekaratharva

      07/09/2025

      The request validation is robust. It caught a few mismatches in my test client like incorrect data types and missing required fields. Appreciate the detailed error message way more actionable than a generic 400

      • naryad

        07/09/2025

        Tried, the API response is contextual and useful for demos and integration. Can you fetch URL periodically? For any contract drift.