apiaryio/api-blueprint

API Blueprint is a language for describing web APIs in plain text files. The idea is that before you write any server code, you can write a short text document that describes what your API will do: which web addresses it responds to, what requests it accepts, and what responses it sends back. This gives everyone on a project, including non-developers, a shared reference to read and discuss. The format is designed to be simple enough that a product manager or designer could read it without needing to understand programming. A basic example in the README shows that describing a single endpoint takes just four lines. From that description, you can automatically generate a mock server to test against, produce human-readable documentation, and run automated tests, all before writing the actual implementation. GitHub recognizes the API Blueprint format natively, which means files written in it get syntax highlighting and can be searched on GitHub like any other programming language. The file extension used is .apib and the official media type is text/vnd.apiblueprint. The project is open source under the MIT license and was maintained by Apiary, a company focused on API design tooling. The repository itself is not a software library you install and run. It is the specification document that defines what API Blueprint is and how it works, along with tutorials, examples, and a glossary of terms. Separate tools built by the community (listed on the project website) handle parsing, documentation rendering, mocking, and testing. Changes to the specification went through a formal RFC process, where proposed changes were written up and discussed publicly before being adopted. The roadmap was tracked openly on GitHub.