Mattermost vs Slack
Side-by-side comparison of features, pricing, ratings, and alternatives.
Mattermost is an open-source, self‑hostable platform that lets teams communicate in real time while keeping data under their own control. It offers channels, direct messages, and rich media sharing, all designed for privacy‑focused organizations. The platform integrates with developer tools, supports custom plugins, and can be deployed on‑premises or in the cloud, making it a flexible alternative to commercial chat solutions.
Slack is a messaging program designed specifically for the office, developed by Slack Technologies and now owned by Salesforce.
Free tier with message history limits; paid plans from $7.25/user/month.
- Full data ownership with self‑hosting options.
- Open-source code allows extensive customization.
- Rich integration ecosystem for developer tools.
- Cross‑platform clients ensure accessibility.
- Excellent search and channel organization
- Huge app ecosystem
- Reliable and fast
- Great notification controls
- Self‑hosting requires infrastructure and maintenance expertise.
- Advanced enterprise features are behind a paid tier.
- User interface can feel less polished than some commercial rivals.
- Free plan history limit is restrictive
- Can become noisy with too many channels
- Pricing adds up for large teams
What reviewers say
Mattermost Reviews
No reviews yet.
Slack Reviews
4.0 (3)Decent but has rough edges
Slack is solid overall, though it's not perfect. On the plus side, reliable and fast. That said, free plan history limit is restrictive, which held us back from rating it higher.
Solid choice
Been a daily user of Slack for a while now. Great notification controls. One minor gripe: pricing adds up for large teams, but it hasn't been a dealbreaker. Would recommend to anyone considering it.
Solid choice
Slack has quickly become part of our daily workflow. Huge app ecosystem. No major complaints so far. Would recommend to anyone considering it.
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The Verdict
AI-generated from listing dataMattermost offers self‑hosted, open‑source control and compliance at the cost of setup complexity, while Slack provides a ready‑to‑use cloud service with a free tier but less data ownership.
Key differences
- •Mattermost can be self‑hosted for full data control; Slack is SaaS only.
- •Mattermost is open‑source and customizable; Slack is closed source.
- •Slack includes a free tier with limited history; Mattermost pricing is not disclosed.
- •Mattermost focuses on developer‑tool integrations and compliance; Slack offers a broader app ecosystem and built‑in audio/video huddles.
- •User interface polish: Slack is generally more refined than Mattermost.
Pricing & value
Slack offers a free tier and known paid plans; Mattermost pricing is not specified, making cost comparison unfavorable for Slack.
Ease of use / learning curve
Slack’s UI is described as more polished; Mattermost’s interface can feel less refined, increasing onboarding effort.
Features & depth
Mattermost provides built‑in compliance, retention policies, and self‑hosting options not available in Slack.
Integrations & ecosystem
Slack lists thousands of integrations via its App Directory; Mattermost lists a limited set of developer‑tool integrations.
Collaboration
Both support channel‑based messaging, threaded conversations, and file sharing; each has unique extras (huddles vs compliance).
Security & privacy
Mattermost’s self‑hosting gives full data ownership; Slack’s cloud model offers less direct control over data.
Choose Mattermost if…
Enterprises or regulated teams that need on‑prem data control and compliance.
Choose Slack if…
Organizations that want quick, low‑maintenance collaboration with a free option.
Common questions
Can I try the product for free?
Slack provides a free tier with limited message history; Mattermost pricing is not disclosed, so a free trial is not confirmed.
Which platform gives me full control over my data?
Mattermost, because it can be deployed on your own servers or private cloud for complete data ownership.
Do both tools integrate with GitHub?
Yes. Mattermost lists GitHub as a key integration; Slack also lists GitHub among its thousands of integrations.