What is a Postman Collection?

Collections group related requests (say, every endpoint of a single API) into folders, and each request can carry variables, pre-request scripts, and test assertions that run automatically after the response comes back — turning what could be a loose pile of manual API calls into a repeatable, versioned test suite. Environment variables let the same collection run against a local dev server, a staging environment, and production just by swapping which environment is active. Collections are also a common way to document and hand off an API: exporting a collection alongside an API gives another developer (or an AI agent, increasingly) working, runnable examples rather than just static prose documentation, since each request can actually be executed against a live server to confirm it still behaves as documented. Because collections often contain real auth tokens or example payloads with sensitive fields, sharing or committing them needs the same care as any other secret-adjacent artifact — using environment variables for credentials rather than hardcoding them into the request itself is standard practice.