Freemium

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

Slack

Freemium

Slack is a cloud-based team collaboration tool.

Basecamp

Commercial

Basecamp is a project management web app.

Mattermost

Open Source

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

eXo Platform

Commercial

eXo Platform is an open source, standard-based, Enterprise Social Collaboration Platform.

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…

Priority Matrix

Commercial

Priority Matrix is a time management software application that is supported on a number of platforms, including Microsoft Windows, Mac OS X, Android, and iOS.…

Flock

Freemium

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

Fleep

Freemium

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

Zulip

Open Source

Zulip is a chat and collaborative software.

Gitter

Freemium

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

Trello

Freemium

Trello is a web based project management solution.

Discord

Free

Discord is a freeware proprietary VoIP application designed for gaming communities.

Glip

Freemium

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

Rocket.Chat

Open Source

Rocket.Chat free open source chat solution.

Quip

Commercial

Quip is a collaborative productivity software suite for mobile and the Web.

Hibox

Freemium

Hibox provides task management, business chat and video calls.

Yammer

Commercial

Yammer is a freemium enterprise social networking service used for private communication within organizations.

Grape

Commercial

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…