Postman

Postman is the world's most popular API development platform, used by over 30 million developers and 500,000 organizations. What started in 2014 as a simple Chrome extension for testing API endpoints has evolved into a comprehensive platform covering the entire API lifecycle: design, documentation, testing, monitoring, and collaboration. Postman's intuitive interface makes it the default tool for anyone who works with APIs — backend developers, frontend developers, QA engineers, DevOps teams, and even non-technical stakeholders who need to understand or verify API behavior.

Request Building and Testing

Postman's core function is sending HTTP requests and inspecting responses. You specify the method (GET, POST, PUT, PATCH, DELETE), URL, headers, query parameters, and body (JSON, form data, raw, binary, GraphQL). The response viewer shows the body (formatted JSON, XML, HTML), headers, status code, response time, and size. Pre-request scripts (JavaScript) let you dynamically generate values, set variables, or handle authentication before the request fires. Post-response test scripts let you write assertions: check status codes, validate JSON schema, verify response values, and chain requests by extracting values from responses. This request-building experience is so intuitive that "let me check in Postman" has become a standard phrase in API development.

Collections and Environments

Collections organize related API requests into folders — all endpoints for a user service, a complete API workflow, or a test suite. Collections can be shared with team members, exported as JSON, or published as documentation. Environments store variable sets (base URLs, API keys, tokens) that you swap between contexts: development, staging, production. A collection using {{base_url}}/api/users works against any environment by changing the active environment. This separation of requests from configuration is fundamental to productive API work and something command-line tools like cURL handle poorly.

Automated Testing with Newman

Newman is Postman's command-line collection runner. It executes Postman collections from the terminal, making it perfect for CI/CD integration. Run your API test suite as part of every build: push code, deploy, run Newman against the deployed API, and fail the build if tests don't pass. Newman outputs results in multiple formats (CLI, JSON, JUnit XML, HTML) for integration with CI systems. This transforms Postman collections from manual testing tools into automated API test suites without learning a separate testing framework.

API Documentation

Postman automatically generates API documentation from collections. Each request's method, URL, headers, parameters, body examples, and test assertions become documentation pages with a clean, browsable interface. You can add descriptions to collections, folders, and individual requests in Markdown. The generated docs include code snippets in multiple languages (cURL, JavaScript, Python, Go, Java, etc.) and a "Run in Postman" button that imports the collection directly into a reader's Postman workspace. For teams that struggle to keep API docs updated, Postman's approach — documentation generated from the same collections you use for testing — ensures docs and behavior stay in sync.

Mock Servers and Monitoring

Postman Mock Servers let you simulate API responses before the backend is built. Define expected responses for each endpoint, and Postman creates a mock URL that returns those responses. Frontend teams can develop against the mock while the backend team builds the real API. Monitors run collections on a schedule (hourly, daily) and alert you when endpoints fail, slow down, or return unexpected responses. This provides basic API health monitoring without deploying separate monitoring infrastructure.

Pricing

Postman's free plan is generous: unlimited collections, environments, and mock server calls (1,000/month), 25 monitors, and 3 shared workspaces. The Basic plan at $14/user/month adds more collaboration features, higher limits, and role-based access. The Professional plan at $29/user/month includes advanced monitoring, custom domains for documentation, and integrations. Enterprise (custom pricing) adds SSO, audit logs, and advanced security controls. For individual developers and small teams, the free plan covers the vast majority of API development needs.

Limitations

Postman's shift from a desktop app to a cloud-connected platform has frustrated some users. Collections are now synced to Postman's cloud by default, raising security concerns for teams working with sensitive APIs. The lightweight scratchpad mode (offline) is limited in features. Performance can degrade with very large collections (thousands of requests). Postman's scope has expanded into API design (OpenAPI editor), governance, and flow building — features that feel bolted on rather than core. For developers who just want to send requests and write tests, the UI has become increasingly cluttered with features they don't use.