Mattermost vs Slack: Which is Better in 2026?
Choosing between Mattermost and Slack comes down to understanding what each tool does best. This comparison breaks down the key differences so you can make an informed decision based on your specific needs, not marketing claims.
Bottom line: Slack is our overall pick for communication workflows. Pick Mattermost if you need a free tier to start with.
Short on time? Here's the quick answer
We've tested both tools. Here's who should pick what:
Mattermost
Open-source team collaboration platform
Best for you if:
- • Mattermost is an open-source messaging platform for secure team collaboration
- • It provides channels, threads, and integrations with self-hosting options
Slack
Central hub for workplace communication and collaboration
Best for you if:
- • Channel-based messaging platform with 2,600+ integrations, huddles, Canvas docs, and workflow automation
- • Free plan covers basics (90-day history, 10 apps); paid plans start at $7.25/user/month with unlimited history
| At a Glance |  Mattermost |  Slack |
|---|---|---|
Starts at | $10/moProfessional | $7.25/user/month (annual)Pro |
Best For | Communication | Communication |
Rating | - | - |
Choose Mattermost or Slack?
Choose Mattermost if
Open-source team collaboration platform
- Open source Slack alternative
- Self-hostable
- Good for compliance
Choose Slack if
Central hub for workplace communication and collaboration
- Intuitive interface with low learning curve, most teams adopt it within days
- Deepest third-party integration ecosystem of any team chat tool (2,600+ apps)
- Slack Connect eliminates email chains with external partners via shared channels
- Budget matters ($7.25/user/month (annual) vs $10/mo)
| Feature | Mattermost | Slack |
|---|---|---|
| Pricing Model | Freemium | Freemium |
| User Rating | ★4.3/5 596 reviews | ★4.5/5 61,908 reviews |
| Categories | CommunicationTeam Chat | CommunicationProductivity |
In-Depth Analysis
Mattermost
Open-source team collaboration platform
Strengths
- +Open source Slack alternative
- +Self-hostable
- +Good for compliance
- +No per-user cloud cost
- +Customizable
Weaknesses
- -Less polished than Slack
- -Smaller integration library
- -Self-hosting required for best value
- -Learning curve
- -Community smaller
Key features
Slack
Central hub for workplace communication and collaboration
Strengths
- +Intuitive interface with low learning curve, most teams adopt it within days
- +Deepest third-party integration ecosystem of any team chat tool (2,600+ apps)
- +Slack Connect eliminates email chains with external partners via shared channels
- +Powerful search across all messages, files, and connected apps from one bar
- +Workflow Builder lets non-technical users automate routine processes
Weaknesses
- -Free plan limits message history to 90 days and allows only 10 app integrations
- -Notification overload in large workspaces, channels can become noisy without discipline
- -Pricing adds up quickly for large teams at $7.25-$12.50/user/month
- -No built-in project management, still requires separate tools like Asana or Jira
- -Slack AI features require Business+ or Enterprise plans, not available on Pro
Key features
Pricing: Mattermost vs Slack
| Plan | Mattermost | Slack |
|---|---|---|
| Tier 1 | Free Free | Free Free |
| Tier 2 | $10 Professional | $7.25 /user/month (annual) Pro |
| Tier 3 | Custom Enterprise | $15 /user/month (annual) Business+ |
| Tier 4 | N/A | custom Enterprise+ |
Pricing verified from each vendor's public pricing page. Compare in detail on Mattermost pricing and Slack pricing.
Who Should Use What?
On a budget?
Both are freemium. Compare plans on their websites.
Go with: Mattermost
Want the highest-rated option?
Neither has user reviews yet.
Go with: Mattermost
Value user reviews?
Neither has user reviews yet.
Go with: Slack
3 Questions to Help You Decide
What's your budget?
Both are freemium. Pricing won't help you decide here.
What's your use case?
Both are communication tools. Compare their specific features to decide.
How important are ratings?
Neither has user reviews yet.
Key Takeaways
Slack
- Higher user rating: 4.5/5 vs 4.3/5
- Larger review base (61,908 reviews)
- Free tier available
- Our pick for this comparison
Mattermost
- Choose if you want open-source team collaboration platform
The Bottom Line
Slack is our pick.
Frequently Asked Questions
Is Mattermost or Slack better?
Slack is rated in our evaluation. Both are freemium.
What are Mattermost and Slack used for?
Mattermost: Open-source team collaboration platform. Slack: Central hub for workplace communication and collaboration.
What does Mattermost cost vs Slack?
Mattermost is freemium (free tier + paid plans). Slack is freemium (free tier + paid plans). Visit their websites for detailed pricing.