Benno MailArchiv is an email archiving system that archives messages automatically in the background and offers fast full-text search. According to the vendor, it archives business email in line with the German GoBD rules, and archived emails cannot be altered afterwards. Self-hosted, it works with any mail and groupware server; as Benno Cloud Enterprise, a software-as-a-service offering, it connects to Microsoft 365 and Exchange Online, a company's own mail server or IMAP mailboxes. Hosters and resellers can offer it to their customers.
Benno is developed by LWsystems GmbH & Co. KG in Bad Iburg, Germany, an IT company focused on open source. The Core (backend) and the WebApp are published under the AGPLv3, while the REST middleware module is proprietary and has no published source code. For the cloud offering, the server location is given as Germany; with self-hosting the archive stays on your own infrastructure. There is no non-European parent company, so European organisations can run the archive themselves or have it hosted in Germany.