Codeacademy has just launched its program for APIs for open release. The well known Codecademy is a team of hackers working hard to build a better way for anyone to teach, and learn, how to code. Their investors have been Union Square Ventures, Index Ventures, Kleiner Perkins, O'Reilly, SV Angel, Thrive Capital, CrunchFund, Collaborative Fund, Founder Collective, Yuri Milner, Vivi Nevo, Richard Branson, and several others.
In recent years, API specification/description formats, most notably OpenAPI, have become more common and have helped standardize the once-murky definition of an API. This standardization allowed the creation of a broad ecosystem of tooling for auto-generated testing and documentation.