Zulip

Open SourceApache-2.0Self-hostable

Team chat with a unique topic-based threading model that keeps async conversations organized — a thoughtful open-source alternative to Slack for distributed teams.

Open source alternative to

Slack

Visit Zulip View source

About Zulip

Zulip's whole design revolves around one idea: channel-only chat gets noisy, so every message belongs to a topic within a channel, and conversations stay organized as threads instead of one continuous scroll.

That model makes Zulip particularly well suited to distributed and async-first teams working across time zones. It's fully open source, self-hostable, and offers a genuinely generous free tier for both self-hosted and cloud deployments.

Key features

Topic-based threading — Every message belongs to a topic, keeping parallel conversations readable instead of one long scroll.
Fully searchable history — Every conversation is indexed and searchable, making async catch-up genuinely practical.
Self-hosted or cloud — Run Zulip on your own servers or use Zulip Cloud, with the same open-source core either way.
Keyboard-first UX — A keyboard-driven interface designed for people who live in chat all day.

The honest read

What we like

Threading model genuinely reduces noise versus channel-only chat
Generous free tier, self-hosted or cloud
Strong fit for distributed, async-first teams
Backed by an active, long-running open-source community
Fully searchable conversation history

Worth knowing

Threading model has a learning curve for Slack switchers
Smaller third-party integration marketplace
Self-hosting needs Postgres, Redis and Django stack knowledge
Mobile apps lag slightly behind the web experience

FAQ

Is Zulip free to use?

Yes — Zulip is free and open source, with a generous free tier available both self-hosted and on Zulip Cloud.

What makes Zulip's threading different?

Every message in Zulip belongs to a specific topic within a channel, so parallel conversations stay organized instead of blending into one continuous stream like typical channel-based chat.

Can I self-host Zulip?

Yes — Zulip ships an official Docker setup for self-hosting on your own infrastructure.

Is Zulip good for distributed teams?

Yes — its topic-based threading and fully searchable history are particularly well suited to async, distributed teams working across time zones.