Mattermost

Open-source platform for high-trust collaboration

Data verified Sep 15, 2026

Pundit
Score

#10 Trending in Communication & ChatAlternatives

Editorial Verdict

AI-researched, not hands-on tested

Mattermost's self-hosted flexibility is genuinely real -- stable, competitively priced, and supports async workflows without vendor lock-in. The honest tradeoff: self-hosting adds real operational overhead for upgrades and backups, the plugin ecosystem is thinner than Slack's or Teams', and there's no built-in video conferencing without an external integration.

Reviewed by AIToolPundit Editorial Team · last verified October 2026

About Mattermost

Mattermost is the open-source platform for secure, high-trust collaboration. Used by NASA, Airbus, and the US Department of Defense, Mattermost provides Slack-like collaboration with on-premises deployment for security-conscious teams.

Screenshots

Commonly Cited Strengths & Limitations

Strengths

Stable, flexible, and competitively priced platform
Self-manageable, making it easier to investigate problems
Supports asynchronous and sustainable ways of working

Limitations

UI feels dated and less polished than newer collaboration tools
Self-hosting adds operational overhead for upgrades, backups, and plugin management
Plugin ecosystem and integrations are more limited than Slack or Teams
Mobile app can be clunky and slow, with delayed push notifications and no offline access
Steep learning curve and technical effort required to set up and manage
Lacks built-in video conferencing without external integration
Has user and message limits (which spawned forks like Mostlymatter)

Common Use Cases

Integrated Security Operations
Out-of-Band Incident Response
Self-Sovereign Collaboration
Mission-Critical ChatOps
Real-Time DevSecOps Collaboration
Purpose-Built Collaboration Hub
Command + Control

Details

Pricing Model: Contact Sales
Starting Price: Free
Founded: 2016
Team Size: 201-500
Headquarters: Palo Alto, CA
Platforms: WebiOSAndroidMacWindowsLinuxSelf-hosted
Category: Communication & Chat

Who is Mattermost for?

Defense and National Security Teams

Militaries and government agencies use Mattermost for sovereign, air-gapped collaboration and command and control across personnel, contractors, and mission partners.

Security Operations Teams

Understaffed security teams use it to streamline incident collaboration and accelerate detection, response, and remediation workflows.

Critical Infrastructure Operators

Critical infrastructure and intelligence enterprises use self-hosted deployments to keep sensitive data controlled and maintain resilience during incidents.

Frequently Asked Questions

Is Mattermost free?

Mattermost offers a free plan, with paid plans starting at Free.

Does Mattermost offer a free trial?

Yes, Mattermost offers a free trial.

Does Mattermost have an API?

Yes, Mattermost provides an API for developers.

What platforms does Mattermost support?

Mattermost is available on Web, iOS, Android, Mac, Windows, Linux, Self-hosted.

What does Mattermost integrate with?

Mattermost integrates with MS Teams, Atlassian, GitLab, Pexip, Fujitsu.

Is Mattermost cloud-based or self-hosted?

Mattermost is offered as both cloud and self-hosted (hybrid) deployment.

What are the downsides of Mattermost?

UI feels dated and less polished than newer collaboration tools Also, Self-hosting adds operational overhead for upgrades, backups, and plugin management

Who is Mattermost best for?

Mattermost is best suited for Defense and National Security Teams, Security Operations Teams, Critical Infrastructure Operators.

What can I use Mattermost for?

Common uses for Mattermost include integrated security operations, out-of-band incident response, self-sovereign collaboration, mission-critical chatops.

How does Mattermost compare to Slack?

Mattermost and Slack are both used for communication & chat -- specifically team communication tools. See the full side-by-side comparison for pricing and feature differences.