Zulip vs Rocket.Chat
Both are free/open-source alternatives to Slack. Here's how they stack up — verified facts, no spin.
88
Zulip
Threaded team chat that keeps conversations organized.
Zulip is an Apache-2.0 open-source chat app whose topic-based threading model keeps busy teams' discussions searchable and organized. Self-host it or use the hosted option.
85
Rocket.Chat
MIT-licensed, highly customizable team communication.
Rocket.Chat is a permissively licensed (MIT) open-source communications platform you can self-host and reshape freely, with chat, voice, and omnichannel features.
Side by side
| Zulip | Rocket.Chat | |
|---|---|---|
| Sovereignty Score | 88 | 85 |
| Open source | Yes | Yes |
| Self-hostable | Yes | Yes |
| Local-first | Yes | Yes |
| License | Apache-2.0 | MIT |
| Pricing | Free self-host; paid cloud | Free self-host; paid cloud/enterprise |
The verdict
Zulip edges it on the Sovereignty Score, but the right pick depends on the trade-offs below.
Zulip
Strengths
- +Excellent threading model
- +Permissive Apache-2.0 license
- +Great for async teams
Trade-offs
- −Threading is a mental-model shift
- −Smaller ecosystem than Slack
Rocket.Chat
Strengths
- +Permissive MIT license
- +Very customizable and extensible
- +Omnichannel features
Trade-offs
- −Broad feature set can feel heavy
- −Some capabilities gated to paid tiers
More Slack head-to-heads
Facts verified 2026-07-04. Licenses and pricing change — spotted something out of date? That's a correction we want.