eris VS unrealircd

I added native Tor Onion Service support to the Go IRC server Eris which will work if you build from the master branch: https://github.com/prologic/eris. It uses https://github.com/cretz/bine which is a wonderful Go library for working with Tor services to do all the configuration pretty much automatically. The example config has an example .onion configuration, commented out. It also has I2P support of that interests you at all. In these modes it actually works with the hidden service addresses directly and hypothetically it doesn't actually know an IP address to leak, barring an exploit.

UnrealIRCD front-ended by TheLounge web interface that has history would fit what you described, but the setup is not super quick. No registration would be required, TheLounge provides chat persistence. Both are open source. Visitors would not need to be technical and would not need to know IRC commands. Rooms can be deleted by the channel operator. TheLounge is browser based and does not require any additional software.

[1] - https://www.unrealircd.org/ https://github.com/unrealircd/unrealircd/

[2] - https://thelounge.chat/ https://github.com/thelounge

Trivial. Set up your favorite IRC server, UnrealIRCd would be fine, then create a tor onion service, but instead of forwarding port 80 (HTTP), you'd forward 6667 (IRC). Done.