A word of warning about Apple’s background app restrictions
Apple imposes severe limits on applications written for iOS. Under Apple’s strict rules, very few applications qualify for background data or for exemption from automatic suspension. Generally, in the case of chat applications, Apple’s stance is that those applications must be implemented with push notifications.
As mobile push notifications are obviously not part of the IRC protocol, this means that any application that wants to evade these restrictions has to either provide a proxy for all of its users, require its users to set up a proxy for for themselves, or be specific to one IRC network, which provides the requisite push support.
Some applications have tried to cheat these rules over the years by playing inaudible tones over the speaker in order to be classed as audio streaming apps. Apple however, considers this a violation of the app store guidelines.
Unfortunately, this stance from Apple leaves virtually all of the iOS clients almost unusable. This is not a fault of the application developers, it is entirely a result of Apple’s draconian platform restrictions.
Colloquy, one of the staples of MacOS desktop clients, also makes an appearance on iOS in the form of a mobile version. There is support for push notifications using a special bouncer to allow background connectivity without falling victim to Apple’s aggressive app suspend, but you’ll have to run the bouncer on a desktop system or dedicated server of your own in order to get it to work.
Also a transplant from the MacOS desktop, LimeChat is an IRC client for all iOS devices. It supports SSL connections and SASL authentication, as well as automatic nickserv authentication on non-SASL networks.
IRCCloud, which is also listed under our web clients section, is a “hosted” client running on IRCCloud’s servers, with web, iOS, and Android apps available to access the service. Free and paid versions of the service exist, with paid versions offering persistent connections, push notifications, stored message history, and synchronization between multiple clients
As IRCCloud essentially works as an IRC proxy, it’s able to work around the iOS platform restrictions on background data - if you have a paid account with them.