Application Programming Interfaces
The place where you persist data (See Also: persistence, storage)
For mostly static binaries, use IPFS (fixed paths on the filesystem is ideal. Need a place to safely track metadata)
For documents that change, use git and .md
For relationships and metadata, use a real database. Postgres seems hard to beat for this.
DBs are Databases.
Databases often tie in closely to the API side.
Try Open API (previously known as Swagger).
Or just text.
The best way to ensure that your API documentation is current and accurate is to embed it within your API implementation and then generate the documentation using literate programming techniques, or a framework such as http://apidocjs.com/, http://swagger.io/, or http://raml.org/index.html.
via: https://apiguide.readthedocs.io/en/latest/build_and_publish/documentation.html Document your API — API Design Guide 0.1 documentation
The Best APIs are Built with Swagger Tools | Swagger
API Resources | Swagger
About Swagger Specification | Documentation | Swagger | Swagger
Welcome | RAML