# Zulip help center

Zulip is a group chat app. Its most distinctive characteristic is that
conversation within an organization is divided into “**streams**”
and further subdivided into “**topics**”, so that
much finer-grained conversations are possible than with IRC or other
chat tools.

Most people use Zulip on the Web. There are also mobile apps for
Android/iOS, and desktop apps for Mac/Linux/Windows, which can be
downloaded [here](https://zulip.com/apps/).

One Zulip account, associated with a particular company, project, or team,
is known as an **organization**.

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