It was asked a couple of months ago, but given the AI enshittification, it seems a good time to ask again.
I looked around and found:
- Pinetta is/was in development but seems dead with only an alpha release. I am chasing this up on Matrix. edit: Apparently still, technically, active although progress has been slow
- Pinry is a FOSS alternative, but not federated, that seems dormant. However, it works and is in Python, so someone could bolt an AP server to it, he says airily.
If you find one, keep up updated! It’s one of the things where you really need a critical mass already for it to be useful so it’s hard to kick off.
Apparently, Pinetta is still active. There is an alpha release but it seems like the devs were struggling with time limitations and getting the AP protocol right. It is in Python if anyone wants to take a look.