The best Team Chat
Every option ranked — open-source, self-hostable, and commercial — by our transparent Sovereignty Score, with honest trade-offs so you choose what fits you, not us.
Own your team's communication on infrastructure you run.
L5Applications — layer 5 of the AI stack- 1
Mattermost
Top pickOpen sourceSelf-hosted team chat built for security-conscious orgs.
Free self-host; paid Enterprise · in our Slack comparison →
What is Mattermost? →88sovereignty - 2
Zulip
Open sourceThreaded team chat that keeps conversations organized.
Free self-host; paid cloud · in our Slack comparison →
What is Zulip? →88sovereignty - 3
Rocket.Chat
Open sourceMIT-licensed, highly customizable team communication.
Free self-host; paid cloud/enterprise · in our Slack comparison →
What is Rocket.Chat? →85sovereignty
Is it free?
The free tier, its real limits and where you start paying — read from each vendor's own pricing page and dated.
Run these yourself
What each one actually needs — real RAM, honest running cost, and the setup time nobody quotes.
- Self-hosting Mattermost 4 GB for a team of 50 with PostgreSQL on the same box
- Self-hosting Zulip 4 GB for a small organisation
- Self-hosting Rocket.Chat 6 GB with MongoDB on the same machine
Replacing a specific tool?
Head-to-head comparisons for each popular team chat product.
Straight head-to-heads
Two team chat tools, side by side — verified facts and a plain verdict.