Sorry if not really Geany, but its plugin for comparison

[abdulbadii]

So sorry if not really Geany, but its addon (plugin) instead (can't find the forum to properly ask)
Is there as good as git diff algorithm plugin that is capable of comparing two UTF-8 text files pretty fast?

[elextr]

You have been transferred to the plugins repository.

There is a geanyvc plugin that does some version control system interfacing, including Git, but I don't use it so don't know if it will suit you, best you try it.