We host an instance of The Lounge for all of our members. The Lounge is a web-based IRC client which is simple to setup and use. It also has a Progressive Web App available for mobile devices.
We also host an instance of ZNC for those who wish to use their own IRC client but do not want to run their own bouncer. ZNC saves your messages persistently so you do not have to keep your IRC client running 24/7.
For more information, see this page on our wiki.