Psi

Highly customizable open source messaging client with Jabber support, strong security, and multi-network compatibility

The popular messaging application for Facebook users

Lightweight messaging client for seamless chats, group conversations, and media sharing across synced devices

Desktop application that makes it easy to check your feed

Well-rounded VoIP software that enables free communication using any modern device

Version of the popular open-source instant messaging software

Instant messaging and calling app for multiple platforms