Mattermost vs Rocket.Chat: which one to choose in 2026?
Both are open source alternatives to Slack. We compare license, tech stack and features to help you decide which fits your team best.
| Mattermost | Rocket.Chat | |
|---|---|---|
| Category | Productivity | Productivity |
| License | MIT | MIT |
| GitHub stars | 30k | 41k |
| Tech stack | Go, React, PostgreSQL | Node.js, Meteor, MongoDB |
| Replaces | Slack, Microsoft Teams | Slack |
Rocket.Chat has more GitHub stars, which usually indicates a larger community (not necessarily that it's the best option for your use case).
Mattermost
Security-focused team chat and collaboration, an alt. to Slack.
Pros
- Widely used in regulated and government environments
Things to consider
- The Team edition has fewer features than Enterprise
Rocket.Chat
Self-hostable team chat, an alternative to Slack.
Pros
- MIT license
- No message history limit
Things to consider
- MongoDB with a replica set adds operational complexity
Key features
Mattermost
- Playbooks for incident management
- Native CI/CD integrations
- Configurable compliance and retention
Rocket.Chat
- Native channels, threads and video calls
- Bridging with Matrix, Slack and WhatsApp
- Apps and bots via the Rocket.Chat Marketplace