Free Team Chat Software
A relative newcomer to the market, Bitrix24 is considered the most feature rich team chat solution and deservedly so. It has chat, group chat, persistent chat, voice chat and video chat options, but it’s more of a unified communication platform that also supports private social network, telephony, project and document management. The cloud version is 100% for up to 12 users. Self-hosted version that you can put on your server comes with source code and API, so you can modify and integrate it as you wish. Mobile and desktop apps are available for iOS, Android, Mac and PC.
Campfire is a well established player in the niche. Produced by the same team that made Basecamp, Campfire used to have a lot of fans. However, since 37 Signals has made an announcement that they will concentrate on Basecamp alone and will no longer develop either Campfire or Highrise CRM, you’d be wise to stay away from it.
Flowdock is a popular team chat solution for software developers. It integrates with Jira, GitHub, Trello, Redmine and many other tools popular in the niche. Outside the target audience it lacks the features present in popular chat platforms, like video calls and videoconferences.
Cozy is an excellent free chat solution for families. Where as other solutions are mostly geared toward work (collaboration), this one is all about family needs. Family calendar, shopping lists, to do lists, food journal are all there.
Chances are post-Facebook you’ve already heard of WhatsApp. Personally, I dislike WhatsApp and find its group chat features lackluster, but it is being used by hundreds of millions of users worldwide, so it is an option that you should consider.
Source - Free Team Chat Software