API Blueprint
API Blueprint is a high-level API description language using Markdown-based syntax for designing, documenting, and prototyping APIs. Files use the .apib extension with media type text/vnd.apiblueprint. The project was archived in 2024 after being developed by Apiary (acquired by Oracle).
Documentation
Documentation
https://apiblueprint.org/documentation/
GettingStarted
https://apiblueprint.org/documentation/tutorial.html