Postman

Postman is the world's leading API development platform. It lets developers test, document, mock and automate APIs in a unified workflow.

Key features

• HTTP requests: send GET/POST/PUT/DELETE requests with headers, body, params and auth (Bearer, API Key, OAuth).
• Collections: organize requests by project/API. Share with the team.
• Environments: different variables per environment (dev/staging/prod).
• Automated tests: write JavaScript assertions on responses.
• Mock Servers: create a mocked server for frontend dev before the backend is ready.
• Documentation: API documentation that auto-updates from the collection.
• Monitoring: periodic checks that your API still works.
• CLI (Newman): run tests in CI/CD.

Common uses: manual API testing during dev, public API documentation, automated tests in pipelines, debugging integrations, collaboration with frontend teams.

Postman is free for basic use. Paid plans unlock advanced collaboration, multiple mock servers, enterprise management and security.

Popular alternatives: Insomnia, Bruno (open source), HTTPie. But Postman remains the industry standard.