Slack vs Mattermost

Detailed comparison to help you choose the right tool for your needs

S

Slack

Where work happens

4.5
Editorial Rating
M

Mattermost

Open source Slack alternative

4.3
Editorial Rating

Quick Comparison

Rating

4.5
vs
4.3

Starting Price

Free
vs
Free

Pricing Model

freemium
vs
freemium
Feature
Slack
Mattermost
Channels
Direct messages
Huddles (audio/video)
Workflow Builder
2,600+ integrations
Slackbot AI
Team messaging
File sharing
Integrations
Self-hosting
Open source
Mobile apps

Slack Pros

  • Industry-leading integration ecosystem (2000+ apps)
  • Excellent channel organization for topic-based communication
  • Huddles provide low-friction voice conversations
  • Strong search across all historical messages
  • Slack Connect enables secure external collaboration
  • Reliable real-time messaging with good uptime

Slack Cons

  • Free tier limited to 90-day message history
  • Expensive per-seat pricing ($12.50-15/user/month)
  • Desktop app uses significant RAM
  • Notification overload common in active workspaces
  • Threading can fragment important discussions

Mattermost Pros

  • Complete data sovereignty with self-hosted deployment
  • Open source with no vendor lock-in
  • Slack-like familiar interface
  • Air-gapped deployment possible for high-security orgs
  • Strong compliance and audit logging
  • Active community and development

Mattermost Cons

  • Self-hosting requires significant DevOps expertise
  • Mobile apps noticeably inferior to Slack/Teams
  • Smaller app ecosystem than commercial alternatives
  • Complex initial setup
  • Performance depends heavily on server resources

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