Top Alternatives to iMessage

Skype is an instant messaging and VOIP (Voice Over Internet Protocol) client to communicate with people in a distant place.

Pidgin is a free and open-source chat client which supports AIM, Google Talk, ICQ, XMPP protocols.

Adium is an Open source multi-protocol instant messaging client for Mac OS X, supports MSN, Jabber, Yahoo! and other networks.

Digsby provides you with IM, email and Social networks in one easy to use application.

Miranda IM is an open source multiprotocol instant messaging application, designed for Microsoft Windows.

Facebook Messenger is the official Facebook app that lets you have text conversations with all of your friends on the popular social network.

Empathy is an instant messaging (IM) and voice over IP (VoIP) client which supports text, voice, video, file transfers, and inter-application communication over various IM protocols.

IM+ supports simultaneously major IM services, including Google Talk, Twitter DMs, Yahoo!, AIM/iChat, ICQ, Jabber (and Slack through Jabber), etc.

Psi is a free instant messaging application designed for the XMPP network (including Google Talk). Fast and lightweight, Psi is fully open-source and compatible with Windows, Linux, and Mac OS X.

Wire is a cross-platform, encrypted instant messaging client created by Wire Swiss. It is available for iOS, Android, Linux, Windows, macOS and Web browser clients.

Fring connects with Skype, MSN Messenger, ICQ and Google Talk from your iPhone.

Kik Messenger is an instant messenger software.

Xabber (XMPP and Jabber) is a XMPP client for the Android Operating System.

Disa is your new messaging hub. Conversations from different services can seamlessly be joined together, or disbanded within seconds.