Open source, on-premises, Slack-alternative


We’re a YC-backed indie video game company releasing an open source alternative to Slack.

It’s called “Mattermost” and it’s the team communication service our company’s run on since last year. Like Slack, you can send messages and files across channels, get notifications on unreads and mentions, and search history–all from your PC or smartphone.

Unlike Slack, Mattermost is open source. You can download the code, run it on your own servers, and modify it as you wish.

We built Mattermost to solve our own problems. We open-sourced it because so many of our friends wanted to use our software for different reasons:

Modern messaging
Teams who can’t use SaaS rely on cryptic, decades-old technologies. As an example, the US Army uses mIRC to order missile strikes–not a place to miss notifications! Mattermost modernizes communications when SaaS isn’t an option.

Complete control
SaaS providers can’t keep up with everyone’s feature requests. Some teams need offline support, others want channel folders, others email integration. Mattermost lets you build whatever you need–and keep your data on-premises.

Teams suffer when SaaS companies lose focus. Since it’s open source, Mattermost can endure through its community. If quality declines, anyone can fork the code and take stewardship.

We’re continuing to develop Mattermost–an iOS app is already in the works–and as our features and community grow we plan to offer commercial support and later an advanced enterprise version with Fortune 500 security features and environmental certifications.

We’re so glad to share this with you, and look forward to your comments, feature requests, votes and contributions. If you find bugs, please let us know in the issue tracker. If you like this project, please tweet about us at @mattermosthq.

To learn more:

Thank you so much for reading about our new product,

Warmest regards,

The Mattermost Team (within “SpinPunch”, the YC-backed video game company)

Many thanks to GitLab, RethinkDB, Automattic and AeroFS for the help and advice as we prepared to release this project.


Ian Tien is CEO and co-founder of Mattermost, Inc., an open source platform for secure collaboration across the entire software development lifecycle. Hundreds of thousands of developers around the globe trust Mattermost to increase their productivity by bringing together team communication, task and project management, and workflow orchestration into a unified platform for agile software development.