Conversations Alternatives for Linux

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

Telegram is a free cloud-based instant messaging platform.

Slack is a cloud-based team collaboration tool.

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.

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.

Linphone is a free voice over IP (VoIP) service and SIP client.

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.

ICQ is an open source instant messaging software.

Gajim is an instant messaging client for the XMPP protocol which uses the GTK+ toolkit.

Matrix is an open protocol for real-time communication. It is designed to allow users with accounts at one communications service provider to communicate with users of a different service provider via online chat, Voice over IP, and Videotelephony.

Psi is a cross-platform powerful XMPP/Jabber client (Qt, C++) designed for the Jabber power users. Psi+ is a development branch of Psi IM XMPP/Jabber client.

Blink is the best real-time communications client using the SIP protocol.

Bit Chat is a secure, peer-to-peer, open source instant messenger with end-to-end encryption.

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

Zulip is a chat and collaborative software.

QuteCom (WengoPhone) is a free-software SIP-compliant VoIP client.

YakYak is a desktop chat client for Google Hangouts.