Grape is an REST-like API framework for Ruby. It's designed to run on Rack or complement existing web application frameworks such as Rails and Sinatra by prov…

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

Flowdock is a group chat for teams which integrates with GitHub, Jira, Trello.

Glip is fully searchable, real-time group chat; video chat, task management, file sharing app.

Hibox provides task management, business chat and video calls.

Mattermost is an open source, private cloud Slack-alternative, Workplace messaging for web, PCs and phones. MIT-licensed.

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

Flock is a communication app for teams. Packed with tons of productivity features, Flock drives efficiency and boosts speed of execution.

Gitter is an open source instant messaging and chat room system for developers and users of GitHub repositories.

Hack Chat is a minimal, distraction-free chat application.

HipChat is a web service for internal private online chat and instant messaging.

Qiscus provide everything you need to power up your app with chats.