Mattermost is an open source, on-prem Slack-alternative.

It offers modern communication from behind your firewall, including messaging and file sharing across PCs and phones with archiving and instant search.

Please see the features pages of the Mattermost website for images and further description of the functionality listed below:

• Send messages, comments, files and images across public, private and 1-1 channels
• Personalize notifications for unreads and mentions by channel and keyword
• Use #hashtags to tag and find messages, discussions and files

• Import Slack user accounts and channel archives
• Search public and private channels for historical messages and comments
• View recent mentions of your name, username, nickname, and custom search terms

• Use Mattermost from web-enabled PCs and phones
• Attach sound, video and image files from mobile devices
• Define team-specific branding and color themes across your devices

• Product Vision and Target Audiences - What we're solving and for whom are we building
• Mattermost Forum - For technical questions and answers
• Issue Tracker - For reporting bugs
• Feature Ideas Forum - For sharing ideas for future versions
• Contributuion Guidelines - For contributing code or feedback to the project

Follow us on Twitter at @MattermostHQ.

There are multiple ways to install Mattermost depending on your needs.

• Local Machine Install with Docker - Explore product functionality using a single-container Docker install on a local machine, including Mac OSX, Ubuntu, or Arch Linux). Optionally set up email and upgrade your instance using DockerHub.

• AWS EBS Install with Docker - Explore product functionality using a single-container Docker install for Amazon Web Services Elastic Beanstalk. Optionally set up email and upgrade your instance using DockerHub.

• Developer Machine Setup - Setup your local machine development environment using Docker on Mac OSX or Ubuntu.

Prior to production installation, please review Mattermost system requirements.

• GitLab Mattermost Production Installation - Install Mattermost for production environments bundled with GitLab, a leading open source Git repository, using an omnibus package for Ubuntu 12.04, Ubuntu 14.04, Debian 7, Debian 8, and CentOS 6 (and RedHat/Oracle/Scientific Linux 6), CentOS 7 (and RedHat/Oracle/Scientific Linux 7).

For technical questions and answers, please visit the Mattermost forum.