Zimbra is an email and groupware platform for businesses. It provides email, contacts, calendar and tasks, complemented by file sharing, chat and in-browser document editing. Staff use Zimbra through a web browser, Microsoft Outlook with the Zimbra Connector, mobile devices via ActiveSync or an offline desktop client. Organisations run the platform on premises or in a private cloud, or take it as a cloud or hybrid service through local partners and regional data centres.
Zimbra is developed by Synacor, Inc., a US company based in Buffalo, New York, which acquired Zimbra in 2015. The core server is open source (backend under the GNU GPL v2, frontend under the Common Public Attribution License); advanced features such as high-availability clustering and encryption require a commercial licence. For a European organisation the hosting model is decisive: self-hosting or buying from a European partner keeps the data under your own control. OVHcloud, for example, states that its Zimbra-based email is stored only in European data centres. The software itself continues to be developed by the US company.