Ask HN: What do you use for internal API docs?

Our codebase is sizing up considerably. Moreover, we are moving to different platforms and it's becoming hard to keep track of APIs (private and public) for even the guys who wrote them.

Is there a better way to manage this? Some kind of tool that takes stuff like javadoc and turns it into pretty, searchable interfaces? Something that extracts data from Git repo? An IDE plugin? Anything but the abomination that we're dealing with right now.

I'm sure this is a common pain. How do you manage this?