Codeux Software:

Textual is the world’s most popular application for interacting with Internet Relay Chat (IRC) chatrooms on macOS.

[…]

Textual supports very powerful modern technologies such as the latest IRCv3 specifications, native IPv6, client-side certificate authentication, and much, much more in an easy to navigate, clutter free experience.

Unfortunately (via Jan Lehnardt):

Textual has been sunset and will no longer receive updates.

Previously:

• EU Council Approves New “Chat Control” Mandate
• The End of ICQ
• Mozilla Looking for IRC Replacement

Update (2026-07-10): rob:

IRC (Internet Relay Chat) is having a bit of a revival in one of the communities I participate in (we ditched Discord), but there are not that many clients for Apple devices?

I’m currently using Goguma on mobile and Halloy on desktop, but they both don’t feel like native apps… (technology stack and especially UI/UX)

[…]

Luckily I recently discovered Mango, which looks very promising.

The Mac Genie:

I would still love to have a modern version of Ircle. Nothing else comes close as the best example of a Mac IRC client.