Alternatives to Atomic IRC for all platforms with any license

Pidgin

Pidgin is an easy to use, multi-protocol chat client client used by millions. Connect to AIM, MSN, Yahoo, XMPP, and more chat networks all at once. It has built-in...

Free Open Source Mac Windows Linux BSD PortableApps.com ... Xfce
Support for Multiple protocols Support for Multiple protocols Extensible by Plugins/Extensions Supports XMPP ... Multiple languages Multiple Account support Multiple chat protocols Portable Video calling Voice Call Add a feature

1440 Like
HexChat

HexChat is an IRC client based on XChat for Linux , but unlike XChat it’s completely free for both Windows and Unix-like systems. HexChat was...

Free Open Source Windows Linux BSD PortableApps.com Xfce ... MacPorts XQuartz
Portable Add a feature

175 Like
Trillian

Trillian is an instant messaging app that works on phones, tablets, and desktops while keeping your chats neatly synchronized between all of them! We think conversation...

Freemium Mac Windows Linux Web Android ... iPhone Blackberry iPad
Facebook integration Support for Multiple protocols POP3 Support Team Collaboration Add a feature

270 Like
Adium

Adium is a free and open source instant messaging application for Mac OS X, written using Mac OS Xs Cocoa API, released under the GNU GPL and developed by the Adium...

Free Open Source Mac
Customizable Multiple languages Support for Multiple protocols OTR ... Supports XMPP Tabbed interface Support for Themes Add a feature

329 Like
mIRC

mIRC is a popular Internet Relay Chat client used by millions of people, and thousands of organizations, to communicate, share, play and work with each other on IRC...

Commercial Windows
Colored Text Add a feature

84 Like
XChat for Linux

XChat is an IRC chat program for both Linux and Windows. It allows you to join multiple IRC channels (chat rooms) at the same time, talk publicly, private one-on-one...

Free Open Source Windows Linux
No features added Add a feature

103 Like
- Discontinued The program is no longer updated. Last version, 2.8.8, released in May 2010, can be still downloaded from the official website.
irssi

Irssi is a terminal based IRC client for UNIX systems. It also supports SILC and ICB protocols via plugins.

Free Open Source Mac Windows Linux BSD Cygwin
No features added Add a feature

73 Like
Quassel IRC

Quassel IRC is a modern, cross-platform, distributed IRC client based on the Qt4 framework. Distributed means that one (or multiple) client(s) can attach to and detach...

Free Open Source Mac Windows Linux Self-Hosted
QT Based Standalone Add a feature

42 Like
WeeChat

WeeChat is a fast, light and extensible chat client. It runs on many platforms (including Linux, BSD and Mac OS). WeeChat is: - modular: a lightweight core with...

Free Open Source Mac Linux Android BSD Xfce
Command line interface Extensible by Plugins/Extensions Modular System Support for Multiple protocols Add a feature

29 Like
KVIrc

KVIrc is a free portable IRC client based on the excellent Qt GUI toolkit. KVirc is being written by Szymon Stefanek and the KVIrc Development Team with the contribution...

Free Open Source Mac Windows Linux BSD PortableApps.com
Portable Add a feature

37 Like
IRCCloud

IRCCloud is an IRC client with a future. Stay connected, chat from anywhere, and never miss a message.

Freemium Web Android iPhone
Offline logs Add a feature

15 Like
Kiwi IRC

A hand-crafted IRC client that you can enjoy. Designed to be used easily and freely. More friendly than other webirc clients giving the general public an easy option to...

Free Open Source Web Self-Hosted Chrome
Preconfigurable auto-connect Add a feature

20 Like
Smuxi

Smuxi is an irssi-inspired, flexible, user-friendly and cross-platform IRC client for sophisticated users, targeting the GNOME desktop. Smuxi is based on the...

Free Open Source Mac Windows Linux
No features added Add a feature

29 Like
AdiIRC

c#/csharp IRC CLient. AdiIRC stores all its settings in text files, this way you can grab the adiirc folder and put in on a usb device or external harddrive. Take all...

Free Windows Wine
Portable Add a feature

25 Like
Shout

What is it? Shout is a web IRC client that you host on your own server. What features does it have? * Multiple user support * Stays connected even when you close...

Free Open Source Web Self-Hosted
No features added Add a feature

13 Like
- Discontinued Shout's development has stopped early 2016 and replaced by its official community fork: http://alternativeto.net/software/the-lounge/ . See https://github.com/erming/shout