Thunderbird
Open Source
Thunderbird is a open source mail client developed and maintained by Mozilla foundation.
Adium
Open Source
Adium is an Open source multi-protocol instant messaging client for Mac OS X, supports MSN, Jabber, Yahoo! and other networks.
Facebook Messenger
Free
Facebook Messenger is the official Facebook app that lets you have text conversations with all of your friends on the popular social network.
Psi
Open Source
Psi is a free instant messaging application designed for the XMPP network (including Google Talk). Fast and lightweight, Psi is fully open-source and compatib…
qutIM
Open Source
qutIM is free and open-source multiprotocol (ICQ, Jabber, Mail.Ru, IRC, VKontakte) instant messenger.
Pidgin
Open Source
Pidgin is a free and open-source chat client which supports AIM, Google Talk, ICQ, XMPP protocols.
Miranda IM
Open Source
Miranda IM is an open source multiprotocol instant messaging application, designed for Microsoft Windows.
IM+
Freemium
IM+ supports simultaneously major IM services, including Google Talk, Twitter DMs, Yahoo!, AIM/iChat, ICQ, Jabber (and Slack through Jabber), etc.
Miranda NG
Open Source
Miranda NG is a successor of Miranda IM, a popular multi-protocol instant messaging client for Windows.
Compare Kadu with alternatives
Compare Facebook Messenger and Kadu and decide which is most suitable for you.