I am surprised that Amazon did not add support to more API description formats like RAML or apiblueprint. It is such a key feature. If I wanted to use this service in front of existing APIs, even only one API, I would not want to go through the work of having to redefine all my endpoints through a web form!

Shameless plug: after working on several API projects, I have been researching ways to not have to "code" over and over again what goes into creating endpoints, it became so repetitive. Lately, I turned to RAML (Yaml for REST) and, with 4 other developers, we created an opensource project called Ramses. It creates a fully functional API from a RAML file. It is a bit opinionated but having to "just" edit a Yaml file when building a new API simplified my life. As a bonus, I also get a documentation and a javascript client generated from the same file.

EDIT: forgot the url https://github.com/brandicted/ramses and url of a quick start tutorial: https://realpython.com/blog/python/create-a-rest-api-in-minu...