Postman collection

A collection is the unit Postman organises work in: a folder tree of requests, each with its method, URL, headers, body and optional scripts, plus variables shared across them. Exported, it is a JSON file that another person, a CI job or Newman (Postman's command-line runner) can open and run.

How it works

Requests reference variables such as {{baseUrl}} and {{token}}, which come from an environment, so the same collection runs against local, staging and production. Test scripts attached to a request assert on its response and can set variables for the next one — capturing a token from a login, then using it in every later call.

The misconception

That a collection is documentation. It records what someone once sent, not what the API accepts; a collection can be months out of date and still run green if nobody added the request that would fail. Generating it from the API's OpenAPI document keeps it honest.

Try it here

Every docs page exports a Postman collection for that API, generated from the same definitions as its OpenAPI document. The workspace here works the same way: variables, captures and assertions per saved request.

Sources

Postman collection schema

Other terms

OpenAPI — A machine-readable description of an HTTP API — its paths, parameters, bodies and responses — in JSON or YAML.
REST API — An API that models a system as addressable resources, manipulated with standard HTTP methods.
API endpoint — One URL plus one HTTP method — the smallest unit of an API that a client can call.
Query parameters — The key=value pairs after the ? in a URL, used to filter, sort, page or shape what an endpoint returns.
Path parameters — A variable segment of a URL path, such as the 42 in /orders/42, that identifies one specific resource.
HTTP headers — Name–value metadata sent with every request and response, separate from the body.

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Last updated 16 October 2026