DevDocs - Open source API documentation browser with instant fuzzy search, offline mode, keyboard shortcuts, and more
RAML - RAML is a solution that manages an API lifecycle from design to sharing.
API List - A collective list of APIs. Build something.
README Gen - Most advanced ReadMe generator for your GitHub projects
Apiary - Collaborative design, instant API mock, generated documentation, integrated code samples, debugging and automated testing
Kite - Kite helps you write code faster by bringing the web's programming knowledge into your editor.