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.

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.

Designed for the way technical and operational 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

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.

  • 25,000+ 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.

deployment alternatives asana

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.

Robust integrations with essential third-party developer tools surface exactly the functionality your team needs, when they need it, for better context and faster response times.

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 technical teams need to collaborate — including messaging, Kanban boards, and runbooks — delivered through a unified collaboration suite with unlimited integrations.


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 DevOps, incident resolution, and release management.


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 custom 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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