[jonathonlacher]

Can it handle feeds that aren't available on the public internet?

I have a personal feed that I can connect to over TailScale. But I've found that most podcast clients have a server-side component, which means their backend server must be able to access the feed.

I tried adding my private feed to Podcatcher and am getting "Server Error (500)".

[Bogdanp]

Yup, unfortunately Podcatcher works the same way and that explains why you'd be getting that error, since the server can't access your feed. That's certainly something that it could support though, but you would obviously not get any push notifications for that feed.