Our verdict: Zulip is the best fit for busy communities and teams that drown in fast-moving channels, because every message belongs to a named topic. The software is fully open source and free to self-host; the free cloud plan limits searchable history to 10,000 messages.
About Zulip
Zulip is developed by Kandra Labs and released under the Apache License 2.0. Its main idea is topic-based threading: each channel is split into named topics, so you can catch up on one discussion without scrolling through everything else.
You can use Zulip Cloud or run your own server. The free cloud plan includes 10,000 messages of search history and 5 GB of file storage in total, and many open-source projects, researchers and non-profits qualify for a free Standard plan. Self-hosting is free with all features; mobile push notifications are limited to 10 users for most organizations on the free tier. The Windows app connects to several organizations at once.
What it does well
- Topic-based threading. Every message has a topic, so parallel discussions stay separate.
- Multiple organizations. Sign in to several Zulip servers in one desktop app.
- Integrations. More than 130 native integrations plus webhooks and a REST API.
- Formatting. Markdown with code syntax highlighting, LaTeX, polls and to-do lists.
- Calls through providers. Start voice and video calls with Zoom, Jitsi or BigBlueButton.
Who it is for
Good fit
Open-source communities, research groups and teams with many parallel discussions.
Look elsewhere
Teams that want built-in video calls without a separate call provider.
Pros and cons
Pros
- Fully open source
- Topics make busy chats easy to follow
- Free cloud plan and free self-hosting
- Sponsored free Standard plan for many communities
Cons
- Free cloud plan searches only the last 10,000 messages
- Calls depend on an external provider
- Topic workflow takes some getting used to
How to install Zulip
The direct link is Zulip's small web installer, which downloads and installs the current version. On first launch enter your organization URL, for example yourteam.zulipchat.com, or create a new organization on zulip.com.
Questions about Zulip
Is Zulip free?
Yes. The apps are free and open source. Zulip Cloud has a free plan with limited search history, and self-hosting is free.
What makes Zulip different from Slack?
Every message in a Zulip channel belongs to a topic, which works like a lightweight thread that you can read or mute separately.
