About streams and topics

In Zulip, conversations are organized by conversation streams and topics.

About streams

On Zulip, users communicate with each other in group chats by sending messages to streams, which are similar to conversation threads.

Streams are either:

  • Public - Public streams are for open discussions. Any Zulip user can join any public stream in the organization, and they can view the complete message history of any public stream without joining the stream.
  • Private - Private streams are for confidential discussions and are only visible to users who've been invited to subscribe to them. Users who are not members of a private stream cannot subscribe to the stream, and they also cannot read or send messages to the stream.

Users are subscribed to specific streams in the organization by default, such as the #announce stream. Users can easily view messages from a specific stream; in addition, they can browse their stream subscriptions using the Zulip stream browser.

If they wish to read messages from a stream that they're not subscribed to, users can choose to join a stream. Similarly, if they are not interested in the topics being discussed in a stream, users can choose to unsubscribe from a stream. Users can also customize their stream settings; they can:

If enabled by the organization administrators, users can create streams and invite other users to a stream.

Only organization administrators can modify a stream; they can:

About topics

In each stream, messages are sorted by topics. Topics are specific, fine-grained subjects that fit with the overall subject of the stream that they're sent to. Topics ensure sequential messages about the same thing are threaded together, allowing for better reception for users.

The best stream topics are short and specific. For example, for a bug tracker integration, a good topic would be the bug number; for an integration like Nagios, the service would serve as a good topic.

Users can easily change the topics of the messages that they sent if they sent the message to the wrong topic or if some messages in a topic have gone off-topic.