Kaidan is described as 'Simple, user-friendly Jabber/XMPP client providing a modern user interface using Kirigami and QtQuick. The back-end of Kaidan is written in C++ using the QXmpp XMPP client library and Qt 5' and is a instant messenger in the social & communications category. There are more than 50 alternatives to Kaidan for a variety of platforms, including Mac, Windows, Linux, Android and iPhone apps. The best Kaidan alternative is Element. It's not free, so if you're looking for a free alternative, you could try Element or Pidgin. Other great apps like Kaidan are WhatsApp, HexChat, Conversations and Adium.
GyachE Improved (GyachI) is a fork from Gyach Enhanced Yahoo! client for Linux operating systems. This Yahoo! client supports almost all of the features you would expect to find on the official Windows Yahoo!
United States
Spreed is the worldwide unified web conferencing service offering integrated web and telephone conferencing. It is based on Flash Player. Free service includes 3 attendees and max 1.5h meetings. Single events or monthly service can be purchased.
Germany
EU
FBMessenger is a stand-alone Facebook Messenger app for Linux, very similar to the official Messenger for Windows.
all-in-one Communication and Collaboration Platform. The NYNJA platform combines the benefits of instant chat, video conferencing, screen sharing, file sharing, asset management collaboration, and much more, in one fast, easy and reliable platform.
United States
HoloIRC is an open source IRC client for Android 4.0 and up. It is designed to be as simple to use as possible while being extremely small in size and fairly light in resources. It works with IRC bouncers as well as regular servers.
This is psyced, a scalable multi-protocol multi-casting chat, messaging and social server solution to build decentralized chat networks upon, released as free software. Powerful, not bloated, not too hard to get into.
Atomic is an open source IRC client built for a new age. New features from its heritage of Yaaic, improvements and stuff.
Sim-IM, Simple Instant Messenger, is a multiple protocol instant messenger for MS Windows, GNU/Linux, FreeBSD. Sim-IM supports Jabber/XMPP, Google Talk, ICQ and AIM (Oscar), Yahoo! Messenger and Microsoft Messenger (MSN)
BeagleIM is a lightweight and powerful XMPP client developed by Tigase, Inc. It provides an easy way to start using the XMPP Protocol (formerly known as Jabber) if you've never used it before. Veterans of the protocol will find many features here they are familiar.
United States
Turnkey audio & video call services, with just 1 click. No downloads, data protected in Europe. Solutions for web use, mobiles and connected objects.
Fire is a multi-protocol instant messenger client for Mac OS X based on freely available libraries for each service. Currently Fire handles AOL Instant Messenger®, ICQ®, MSN® Messenger, Jabber, limited IRC, Yahoo!®, and Apple Bonjour communications.
France
