Yes! Zulip Cloud Premium is free for open source projects and a wide variety of non-commercial entities. We also often offer steep discounts to educational institutions, and in other scenarios where users are not being paid a salary. Just contact sales@zulipchat.com and we'd be happy to discuss your situation! You may also be interested in Zulip for open source projects or Zulip for working groups and other part-time communities.
Yes! Some of our biggest fans have hundreds or thousands of users, including Fortune 500 companies like Akamai, and open source communities like The Recurse Center. If you'd like to see a large Zulip in action, the Zulip community server has thousands of accounts and hundreds of weekly active users, and is run on a single machine with 8GB of RAM.
You can always use a credit card to pay, and we can bill by invoice for amounts over $1000.
Yes! We don't want to charge you for a service you aren't actually using. We prorate by the day, and only charge for a user if they have logged on in the last two weeks, even if they haven't explictly been deactivated. If you start on the Premium plan and drop to Free, we will credit your account for the time you have left, that you can use when reactivating your Premium plan in the future.
| Feature | Zulip | Slack | Mattermost | Hipchat |
|---|---|---|---|---|
| Apps for every platform | ||||
| Hundreds of integrations | ||||
| Hosting available | ||||
| Emoji reactions | ||||
| Markdown formatting | ||||
| Topic-based threading | ||||
| Lightning-fast search | ||||
| Free and open source | See below* |
* On Mattermost's licensing: The components of Mattermost are, technically, released under various open source licenses. However, Mattermost's licensing and trademark policy forbids redistributing patched versions of Mattermost without renaming the project. This means, for example, that projects like Debian will never be able to include a Mattermost server package.