It brings social media scheduling, image editing, video editing and a whole bunch of other creator tools into one open-source app. The idea is to create your content and schedule it in the same place, and eventually have it know your brand and help you out as much as possible.
You can self-host it or use the hosted version.
It's not at feature parity with all three, but that’s the direction I’m working towards.
Try it: https://openpo.st Source: https://github.com/getopenpost/openpost