Reviewing common API Editors
medium.com
medium.com
Api blueprint is a great project with a nice ecosystem and tooling around it. You can write the "blueprint" in your editor, serve a mock server, and run regression tests against it, all open source on your own computer. It's easy to setup.
This enables a workflow of "API driven development," where the first milestone is an API blueprint, and then backend engineers can work in parallel with frontend engineers. It can significantly cut development time, especially if you're staffing freelancers. You know the system components will work together because the frontend builds against a mock server, and the backend tests against it.
I've seen a lot of companies roll their own API "Explorers" too: https://dev.twitter.com/rest/tools/console https://developers.facebook.com/tools/ http://products.wolframalpha.com/api/explorer.html
As well as generic Rest API Explorers: http://www.getpostman.com/
Most startups can't afford to spend the time and engineering resource reinventing the wheel for API documentation, especially with the "explorer" or interactive test consoles that have become so popular.
Live editing of API functionality? Much more complicated.
(top level readers: sorry about the double-post)
Here's an interactive API testing tool I made: https://github.com/Mashape/API-Test-Console
[1] https://github.com/tomchristie/django-rest-framework/blob/ma...
One thing you missed was the ability/ease of non-reference guides. No matter how good your API reference is, it's like handing someone a dictionary and telling them to learn English. Topical guides, tutorials, and more are insanely important.
(I'll be at Mashape tonight – see you there?)