They have an API, not sure about channels specifically though.<p><a href="https:&#x2F;&#x2F;zulip.com&#x2F;api&#x2F;" rel="nofollow">https:&#x2F;&#x2F;zulip.com&#x2F;api&#x2F;</a><p><a href="https:&#x2F;&#x2F;zulip.com&#x2F;api&#x2F;endpoints&#x2F;" rel="nofollow">https:&#x2F;&#x2F;zulip.com&#x2F;api&#x2F;endpoints&#x2F;</a>