Discord
Free
Discord is a freeware proprietary VoIP application designed for gaming communities.
Mattermost
Open Source
Mattermost is an open source, private cloud Slack-alternative, Workplace messaging for web, PCs and phones. MIT-licensed.
Ora
Commercial
Ora is a real-time all-in-one workspace for teams.
eXo Platform
Commercial
eXo Platform is an open source, standard-based, Enterprise Social Collaboration Platform.
Zulip
Open Source
Zulip is a chat and collaborative software.
Wickr
Free
Wickr is an instant messenger application.
Jitsi
Open Source
Jitsi (formerly SIP Communicator) is a free and open source multiplatform voice (VoIP), videoconferencing and instant messaging application.
Wire
Free
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 cl…
Rocket.Chat
Open Source
Rocket.Chat free open source chat solution.
Matrix.org
Open Source
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…
Dialog Messenger
Free Personal
Dialog Messenger is a handy and feature-rich enterprise multi-device messenger available for server or cloud.
Gitter
Freemium
Gitter is an open source instant messaging and chat room system for developers and users of GitHub repositories.
Compare Slack with alternatives
Compare Dialog Messenger and Slack and decide which is most suitable for you.