The Open Source Slack Alternative

More than just channel-based messaging. Mattermost gives you everything you need to accelerate mission-critical workflows, complete with on-prem options for full data sovereignty.

Teams that use Mattermost instead of Slack

The only collaboration solution built for mission-critical work

Mattermost brings together full-featured messaging, deep integrations with best-of-breed technical tools, and powerful workflow automation so you spend less time context switching and more time focusing on what matters most.

Unlike Slack, Mattermost is open source and yours to customize. With on-premises deployment options, your data stays in your control — always.

Designed for the way mission-critical teams work

Team Messaging

Team collaboration and technical workflows

Work together effectively with real-time communication, file and code snippet sharing, in-line code syntax highlighting, and workflow automation purpose-built for technical teams.

Platform Overview

Custom Integrations

Flexible integrations with essential technical tools

Execute and automate workflows with flexible, custom integrations with popular technical tools like GitHub, GitLab and ServiceNow.

Platform Overview

Audio & Screen Sharing

Communication that fits your flow

Seamlessly switch from chat to audio calls and screenshare without switching tools.

Platform Overview

Workflow Automation

Orchestrate and execute repeatable processes with better command

Checklist-based process playbooks with workflow orchestration in one unified location.

Platform Overview

Why choose Mattermost over Slack

Find out why mission-critical organizations 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 and increased resilience.
  • 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 adapt 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 with legacy systems.

  • 25,000+ GitHub Stars
  • 30,000+ total contributions
  • 4,000+ contributors

More deployment options than Slack

From government agencies and critical infrastructure 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 give you 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.

deployment alternatives asana

Designed for agile teams

Mattermost goes beyond general-purpose collaboration with features designed to help technical teams collaborate on code, execute sprints, deploy releases, accelerate DevSecOps and ChatOps workflows, and manage incident response.

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.

Robust integrations with essential technical tools surface the exact functionality your team needs, when they need it, for better context and faster response times.

Find out what the community is saying about migrating from Slack to Mattermost.

Don’t just take our word for it

Mattermost vs. Slack Platform Comparison

Learn why technical teams and organizations prefer Mattermost for mission-critical workflows and collaboration.

Software type

Open source software

Open source codebase is supported by community contributors and is publicly available.


Proprietary software

Proprietary software can only be modified by Slack; source code is not publicly available.

Deployment options

On-prem and private SaaS

Deploy on-prem to your own private cloud environment, behind your firewall. Maintain complete control over data, compliance, and security.


Publicly hosted SaaS

Available as a SaaS solution delivered via the public cloud. There aren’t any on-prem or private cloud deployment options.


Feature-rich technical collaboration tools

Everything mission-critical teams need to collaborate — including messaging, audio calls, screenshare, and runbooks — delivered through a secure, purpose-built collaboration hub.


Business messaging

Users have messaging functionality out of the box; third-party tools are available for other purposes but lack tight integration with messaging and require additional licensing and admin fees.


Designed for technical teams

Built for technical and operational collaboration, including DevSecOps, ChatOps, integrated security operations, and incident response.


Designed for general business users

Designed for general collaboration for day-to-day activities.


Fully customizable

Extend Mattermost through free existing and custom apps. Use custom commands and webhooks to extend functionality, add integrations, and implement your own branding.


Some customization

Slack offers an app marketplace that enables you to connect to some other tools. But without access to source code, you can’t customize the app to make it truly yours.


Enterprise-grade security

Keep your environment safe with advanced team permissions, AD/LDAP group sync, complete access to source code, logs of all server records, infrastructure changes, and user activity, and more.


Less control over security

As a SaaS solution delivered through the public cloud, organizations won’t have access to Slack’s source code, which means they have to trust the platform’s security protocols.

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