Mattermost vs Slack: Which Is Better in 2026?
A side-by-side comparison of Mattermost and Slack, two communication tools — what each does, who it's best for, and how to choose between them.
Mattermost
An open-source, self-hostable team messaging platform built for security-conscious and technical organizations.
- Category
- Communication
- Rating
- Not yet rated
- Best for
- team chat, open source, self-hosted
Slack
Channel-based messaging that keeps your team and tools connected.
- Category
- Communication
- Rating
- Not yet rated
- Best for
- chat, team messaging, collaboration
| At a glance | Mattermost | Slack |
|---|---|---|
| What it is | An open-source, self-hostable team messaging platform built for security-conscious and technical organizations. | Channel-based messaging that keeps your team and tools connected. |
| Category | Communication | Communication |
| Type | Software | Software |
| Best for | team chat, open source, self-hosted, collaboration | chat, team messaging, collaboration |
What is Mattermost?
Mattermost is an open-source, self-hostable team messaging and collaboration platform built for organizations that need control, security and customization that typical cloud chat tools can't offer. Frequently described as a self-hosted alternative to Slack, Mattermost gives teams a familiar channel-based messaging experience while keeping all data on infrastructure they own — a crucial requirement for government agencies, defense, financial services, and any organization with strict security, privacy or compliance needs.
Functionally, Mattermost provides what teams expect from modern chat: organized channels, direct messages, threaded conversations, file sharing, search and integrations, plus voice and screen sharing. But its differentiators are control and extensibility. Because it's open source and self-hosted, organizations can deploy it on-premises or in their own cloud, customize and extend it deeply, integrate it tightly with internal systems, and meet rigorous security and data-residency requirements without depending on a third-party vendor's policies.
Mattermost has increasingly focused on technical and operational teams, offering capabilities tailored to developers and DevOps — tight integration with tools like GitLab, support for incident collaboration and "ChatOps" workflows, playbooks for coordinating operational processes, and a platform that fits naturally into engineering environments. This makes it especially popular where chat isn't just for casual conversation but a core part of how technical work and incident response get done. For security-conscious enterprises, regulated industries, and technical teams that value open source and full control over their communication infrastructure, Mattermost offers a powerful, flexible and trustworthy alternative to closed SaaS chat tools — combining the collaboration features teams need with the ownership, customizability and security that demanding organizations require.
What is Slack?
Slack organizes team communication into channels, with huddles, threads and a deep app ecosystem.
Mattermost vs Slack: which should you choose?
Mattermost and Slack both serve the communication space, so the best choice depends on your priorities. Choose Mattermost if you want An open-source, self-hostable team messaging platform built for security-conscious and technical organizations. Choose Slack if you want Channel-based messaging that keeps your team and tools connected.The smartest move is to try each one's free tier or trial on a real task — that's the fastest way to feel the difference and pick the tool you'll actually stick with.
Frequently asked questions
Is Mattermost better than Slack?
It depends on what you need. Mattermost is An open-source, self-hostable team messaging platform built for security-conscious and technical organizations. Slack is Channel-based messaging that keeps your team and tools connected. Both are communication tools, so the right pick comes down to your specific priorities, budget and workflow.
What's the main difference between Mattermost and Slack?
Mattermost focuses on An open-source, self-hostable team messaging platform built for security-conscious and technical organizations. while Slack focuses on Channel-based messaging that keeps your team and tools connected. Read the full breakdown above and check each tool's site for current features and pricing.
Can I use both Mattermost and Slack?
In many cases, yes — teams often use complementary tools together. Whether it makes sense depends on overlap in functionality and your budget. Try the free tier or trial of each to see how they fit your stack before committing.
Which is cheaper, Mattermost or Slack?
Pricing changes often, so check each tool's pricing page for the latest. Many tools offer a free tier or trial, which is the best way to evaluate value for your specific usage before you pay.