Retarus

Retarus is the quiet heavyweight of enterprise fax: a Munich based communications company, founder owned by choice since 1992, that lands alongside the category's giants in analyst evaluations of digital fax while staying almost unknown to small business buyers. That is by design, because it sells exclusively to enterprises. Its cloud fax is built to sit inside business systems, feeding order confirmations out of ERP platforms and referral traffic through hospital record workflows at volumes measured in the millions of pages, and it arrives alongside sibling services for email security and transactional messaging. The compliance file is complete: ISO 27001, SOC 2, HIPAA business associate agreements, and HITRUST, with processing locations selectable by region and a US operation headquartered in New Jersey. The fit boundary is equally clear. There is no self serve product and no published price list, so small offices are shopping the wrong shelf, and its brand is better known in Europe than in the US. For a large organization where fax is plumbing that cannot fail, it belongs on the shortlist.