Describe an API and get a working OpenAPI 3.1 spec back.
Paste a spec, get a plain-English explanation.
Design, lint, visualize, and preview OpenAPI specs.
Validate a spec, score its design, and autofix what it can.
Paste a curl command and get it in your language of choice.
Paste JSON and get TypeScript, Python, or Go types.
Paste a spec, mock every endpoint at once.
Pick a resource, get a live mock endpoint.
Paste JSON or text, get an editable endpoint.
Test REST, SOAP, SSE, and other HTTP-based APIs.
Create and run GraphQL queries and mutations.
Connect to a WebSocket server and send or receive messages.
Publish and subscribe to Socket.IO events.
Invoke unary and streaming methods on a gRPC server.
Connect to remote MCP servers and inspect their capabilities.
Get latency and throughput for any API endpoint.
See if any API, site, or service is down.
Schedule a real monitor for any URL and watch runs land live.
Schedule a real monitor for chained requests and watch runs land live.
Get response time and TTFB for any website.
See when a domain's TLS certificate expires.
See what every response header does to caching, CORS and security.
Hit any endpoint with virtual users and see latency, throughput and errors.
Estimate throughput from users and think time.
Generate mock CSV or JSON test rows for API testing.
Paste a function and get unit tests in your framework of choice.
Paste a payload, learn what every field means.
Every tool here runs in your browser with no signup. When you're ready for the full workflow — Spec Hub, Monitors, performance testing, and the Collection Runner — create a free Postman account and pick up right where you left off.