Graphql. Define the schema, then use a tool to read it. Then federate.
Programming
This magazine is dedicated to discussions on programming languages, software development, and coding. Whether you are a beginner programmer or an experienced developer, this is the place for you. Here you can share your knowledge, ask questions, and engage in discussions on topics such as coding languages, software engineering, web development, and more. From the latest trends and frameworks to tips and tricks for debugging, this category covers a wide range of topics related to programming.
Doxygen. Because we started using it once in a while years ago without looking for alternatives, and it still works. Life is too short to spend time asking if a better tool exists for every possible thing.
The hard part isn't exporting documentation, it is writing useful how to use it. Any hints here would be useful. It is easy to parse C++ compared to the effort of writing useful prose about out APIs. (C++ is one of the hardest languages to parse, but compared to writing)
Readme.io is what we use. The free plan is pretty generous, we’ve been on it for years and not had any need to upgrade for additional features.