Postman

Build, test and document APIs with collections, environments and monitors: the shared workspace for integrations.

Postman is the API platform most developers meet first: a client for building and testing requests, collections that organize them, environments for variables, mock servers and monitors, and a workspace layer for teams to share all of it. It grew from a Chrome extension into the default API toolchain for a generation.

Why it matters to an indie builder: during integration work, Postman is where you learn a third-party API. You build the request, inspect the response, save it as a collection with environment variables for staging and production, then convert it into tests that run in CI. The same artifact documents the integration for the next person, including future you.

A realistic use: integrating a payments provider. A collection holds the create-charge, refund and webhook-simulate requests, each with tests asserting status codes and fields. The monitor runs nightly against sandbox to catch API drift before customers do.

Trade-offs: Postman is heavy, cloud-first and has been moving features behind paid tiers, which is why lighter and open alternatives gained ground. For local-first or privacy-sensitive teams, a Git-friendly client is often a better fit. Compare with Hoppscotch for a free, self-hostable option and Bruno for a repository-native workflow.