Open Collections

OpenCollection is a developer-first specification, pioneered by the team behind Bruno, for defining and sharing collections of API requests as plain, human-readable files. Where the older collection formats leaned on proprietary JSON exports and cloud sync, OpenCollection treats a collection like source code — a set of files you keep in a Git repository, review in a pull request, and diff line by line. It is a quiet but meaningful shift in how the requests, environments, and examples that document an API actually get stored and moved around.

• Git-native, plain-text storage - Requests and environments live as readable files in your repository, so they version, diff, and review like any other code.
• Vendor-neutral by design - The format is open and portable, not locked to a single vendor’s cloud, which lowers the switching cost between tooling.
• Collaboration-first - Because a collection is just files, teams collaborate through the same pull-request workflow they already use for code.
• Complements the design specs - It sits alongside OpenAPI rather than replacing it, capturing concrete example requests where OpenAPI captures the contract.

In real API operations OpenCollection shows up as the layer between the contract and the day-to-day work of calling an API. Teams generate or hand-author collections to document, test, and onboard against an API, then keep them in the same repository as the code and the OpenAPI definition so everything versions together. As the tooling ecosystem fragments across Bruno, Postman, and Insomnia, an open and Git-native collection format is one of the cleaner ways to keep this knowledge portable — and increasingly it doubles as a machine-readable set of worked examples that agents can read to learn how an API is actually used.