Ask HN: What's the fastest way to build an API for language X

Can you be a little more specific. What is the use case?

I have feeling you mean a parser API...but I am not sure.

SWIG http://www.swig.org/. Write API implementation once, in C, then generate bindings for other languages.

Python - Flask Restless

Java - Spring Boot.

I second this. REST/JSON is first class and even adding more complex features like OAuth is fairly easy.

java - jaxrs