Facebook Messenger Alternatives for Mac OS X

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

WhatsApp Messenger is an instant messaging platform owned by Facebook.

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

Tox is a peer-to-peer instant-messaging and video-calling protocol that offers end-to-end encryption.

Trillian is a proprietary multiprotocol instant messaging application.

Viber Free Messenger and Phone Calls.

Signal is the most scalable encryption tool.

Jitsi (formerly SIP Communicator) is a free and open source multiplatform voice (VoIP), videoconferencing and instant messaging application.

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.

Kopete is a multi-protocol, free software instant messaging client released as part of the KDE Software Compilation. Although it can run in numerous environments, it was designed for and integrates with the KDE Plasma Workspaces.

Franz is a free messaging app /former emperor of Austria, that combines chat & messaging services into one application.

ICQ is an open source instant messaging software.

FaceTime is a proprietary videotelephony product developed by Apple Inc. FaceTime Audio is an audio-only version.

WeChat is a social media with instant messaging, commerce and payment services application.

Instantbird is a cross-platform instant messaging client based on Mozillas XULRunner and the open source library libpurple used in Pidgin.

iMessage is an instant messaging service.

qutIM is free and open-source multiprotocol (ICQ, Jabber, Mail.Ru, IRC, VKontakte) instant messenger.

KakaoTalk (Korean: 카카오톡), or sometimes KaTalk, is a free mobile instant messaging application for smartphones with free text and free call features.

Rambox is a free and Open Source messaging and emailing app that combines common web applications into one.

Fleep enables communication within and across organizations, be it your team chats, project communication or 1:1 conversations.

Tencent QQ (QQ) is an instant messaging software service.

Kadu is a free and open source multi-platform instant messaging client that supports Gadu-Gadu, XMPP IM networks and other services based on XMPP like Google Talk.

Coccinella is a free and open-source cross-platform client for the XMPP/Jabber-instant messaging-protocol.

Zulip is a chat and collaborative software.

Dialog Messenger is a handy and feature-rich enterprise multi-device messenger available for server or cloud.

YakYak is a desktop chat client for Google Hangouts.