Criterion for provider selection with growing relevance
For more and more industries and public institutions, the BSI C5 certificate is becoming a relevant or even mandatory criterion when selecting their partners. ‘mailbox has been committed to data security for years. We are therefore particularly pleased that the certificate officially confirms this,’ says Peer Heinlein. ‘Our customers can rely on certified cloud security and the highest level of information security, as evidenced by our ISO 27001 certification and other awards.’
mailbox: ISO 27001 certified and awarded quality seals
mailbox protects its customers' data with state-of-the-art encryption, continuous monitoring and innovative security procedures. Data is stored exclusively on redundant German servers in 100% GDPR compliance. In addition to the BSI C5 certification, mailbox is also ISO/IEC27001 certified. ISO 27001 is the international standard for information security management systems (ISMS). It offers organisations a systematic approach to protecting their information. Specifically, this approach helps to identify, assess and control risks to the confidentiality, integrity and availability of information.
In addition, mailbox 2025 was awarded the ‘Software made in Germany’ and ‘Software hosted in Germany’ quality seals by the German Federal Association of IT SMEs (BITMi). In addition, mailbox has achieved gold status as part of the BSI's Email Security Year 2025. The Heinlein Group company has thus committed itself to the full implementation of state-of-the-art email security standards and has already successfully implemented them. Users of mailbox benefit from the provider's pioneering position and can rely on certified cloud and email security.
About mailbox
mailbox is the digital workplace for secure communication and provides digital sovereignty from Germany for the world. The mailbox Suite integrates email, calendar, contacts, office, video conferencing and drive in one intuitive solution, running exclusively from German data centres.
As a European provider, mailbox completely avoids advertising, tracking and data monetisation, serving businesses, public and educational institutions, resellers and private individuals with highest demands for data protection and digital independence.
mailbox is part of the Heinlein Group, which has been the expert in free and secure communication for over 30 years.
About Heinlein Group:
Heinlein Group, based in Berlin, stands for digital sovereignty, data protection and open source. It brings together the brands Heinlein Support, mailbox, OpenTalk and OpenCloud, which offer many years of expertise in open standards, personal consulting and innovative solutions for secure communication and independent IT infrastructure. Whether email services, video conferencing or file management – Heinlein Group's products are GDPR-compliant, flexible in use and technically state-of-the-art. Together with its hosting, consulting and Heinlein Academy divisions, Heinlein Group covers the entire spectrum for setting up and operating sovereign and resilient IT infrastructures.
For over 30 years, companies, public institutions, educational institutions and providers have placed their trust in the expertise of Heinlein Group. Its offerings create maximum control and transparency, strengthen digital independence and promote sustainable IT development.
