What are some alternatives?
Slack - A messaging app for teams who see through the Earth!
Mattermost - Mattermost is an open source alternative to Slack.
Riot.im - Open source interoperable collaboration app.
Skype - Stay in touch with your family and friends for free on Skype. Download Skype today to chat and call on desktop and mobile.
Glip - Glip is fully searchable, real-time group chat & video chat, task management, file sharing and more, in one easy-to-use app. Get started FREE today.
Telegram - Telegram is a messaging app with a focus on speed and security. It’s superfast, simple and free.