I'm looking for a WEB Framework for REST API in C, that uses Google's Protocol buffers.
I know few Frameworks that uses JSON, like Ulfius and Mongoose, but didn't find one that supports Protobufs.
I expect you just have to go through the pain of adding protocol buffers support to your project and build system yourself. The important thing is probably to pick a get server framework and go from there.
I would have thought culturally frameworks don't fit too well with the C mind-set so much as libraries.
Disclaimer: I am a C++ programmer who only drops down to C libraries if a C++ one isn't available.