Show HN: Mockd – Mock Server for HTTP, gRPC, GraphQL, WebSocket, MQTT, SSE, Soap

I kept ending up running WireMock for REST, some random Node for WebSocket, a hacky gRPC mock and whatever else I needed ad-hoc. So I built one that does all of them. The core is a shared engine (matching, state management, templates, chaos injection) and each protocol is just another interface on top of it. Once that clicked it got fun to add more. The part I'm most interested in feedback on: digital twins. You import a real API's OpenAPI spec, bind endpoints to stateful tables, and get a mock that behaves like the real service. stripe-go runs 49/49 tests against mockd. twilio-go passes 13/13.

As all things tend to start from annoyance, I built this because I got annoyed while at a client with a normal modern stack that integrates with legacy bank SOAP APIs. Your options were basically spin up WireMock or don't test it... Sooo ~120K lines of Go late .. I built mockd, no CGO, Apache 2.0. Single binary, 12ms startup.