Streams and topics

In Zulip, streams determine who gets a message. Topics tell you what the message is about.

Conversation model Who gets it What it's about
Zulip Stream Topic
Email Mailing list Subject line
Slack/IRC Channel -

One big difference is that Zulip organizations typically have more streams than they would email lists, and Zulip topics are much shorter than email subject lines. Here is what it looks like in Zulip.

Streams and topics are the hardest part of Zulip to grasp, but also the most rewarding part of using Zulip.

If you ever find yourself stuck on writing a topic, just pretend you're sending an email, with the topic as the subject line. After a few days you'll get used to a more Zulip-y way of doing things, and your topics will naturally become shorter (2-3 words is optimum) and take less thought to type.

Why topics?

Learning how to chat with topics has a bit of a learning curve, anywhere from a few minutes to a few days. Why bother with something so complicated?

The short answer is that most users spend many hours a day on chat. A little investment up front pays huge dividends in access to a more powerful communication paradigm. A longer answer is here.


When replying to a message, the stream and topic are conveniently pre-filled. Click on a message to reply, or type r to reply to the message under the blue box.

Further reading