mockd

Need to mock HTTP, gRPC, GraphQL, WebSocket, MQTT, SSE, or SOAP APIs while working in Claude? This MCP server gives you programmatic control over mockd, a zero-dependency Go binary that runs all seven protocols from one process. Claude can create stateful CRUD endpoints, import OpenAPI specs to spin up digital twins of Stripe or Twilio, inject chaos patterns like circuit breakers and bandwidth throttling, or configure multi-step stateful flows. You get the full admin API: create mocks, seed data, toggle fault injection, export HAR files. Useful when you're prototyping against third-party APIs that cost money per call, building demos without backend dependencies, or testing edge cases like timeouts and 500s without touching production systems.