The Open Source Slack Alternative

More than just channel-based messaging. We give you everything you need to boost your team’s productivity, complete with on-prem options for full control of your data.

Mattermost Channels, Playbooks, and Boards

Teams that use Mattermost instead of Slack

The only all-in-one solution for team collaboration

Mattermost brings together full-featured messaging, deep integrations with best-of-breed developer toolchains, and powerful workflow automation so you spend less time context switching and more time building.

Unlike Slack, Mattermost is open source and yours to customize – and with on-premise deployment options, your data always stays in your control.

Team messaging + project management + workflow automation


Group and direct messaging with all the features your team loves + developer tool integrations that turn your channels into collaborative CLI.


Kanban-style boards for teams to manage tasks, hit milestones, and drive alignment across complex workflows.


Checklist-based workflow management for when your team’s processes require collaboration and structure.

Why choose Mattermost over Slack

Versatile Collaboration

  • Flexible tools designed for the way your team works.
  • Fewer fragmented tools + robust workflows makes complex operations easy.

Open Source

  • Customize your workspace to your specific needs.
  • Innovation and support from a vibrant OSS community of developers.

On-Prem Deployment

  • Deploy behind your firewall for superior security.
  • The only collaboration solution where you can maintain data control and sovereignty.

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The flexibility and extensibility that Slack lacks

Your tools should be tailored to fit the way your team works. Mattermost is the only open source collaboration platform that gives you the ability to customize, extend, and build bespoke integrations — including legacy systems.

  • 34,000+ GitHub™ Stars
  • 30,000+ total contributions
  • 4,000+ contributors

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More deployment options than Slack

From governments and intelligence organizations to financial services and healthcare companies, teams in high-security and regulated industries trust Mattermost for secure collaboration.

Choose from on-prem and private cloud deployment options that meet your security and compliance needs and let you retain full control and sovereignty over your data at all times. Deploy in air-gapped and other high-security environments, use EMM for secure mobile comms, and define granular controls for enterprise data archiving to keep data properly secured and accessed.

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Designed for agile teams

Mattermost goes beyond general purpose collaboration, with features designed to help developer teams collaborate on code, execute sprints, deploy releases, and manage outages and support escalations.

Channel-based collaboration with powerful automation and tool integrations to raise messaging to the level of a CLI.

Playbooks for structured workflows that require repeatable execution with predictable outcomes.

Boards for project and product teams that need to manage deliverables, hit their milestones, and stay aligned.

Slash your Slack bill with Mattermost

See Pricing Plans »

Great economics for teams getting started

Save as much as 70% on developer tools while helping your team reclaim 39% of their time for rapid and sustained ROI.

More value for larger scale teams

Mattermost Professional and Slack Business+ have comparable messaging feature sets, including SSO with SAML, advanced permissions, and read-only channels. Plus, Mattermost includes Playbooks and Boards and charges only a portion of the price of Slack.

Key enterprise features missing from Slack

Mattermost includes a number of advanced features in our Enterprise plan not available in Slack Enterprise Grid including AD/LDAP group sync, OpenID connect, custom admin roles, advanced team permissions, and ID-only push notifications.

Don’t just take our word for it

Try Mattermost for free.