Retarus

Privately owned Munich vendor marketed explicitly as email security 'made in Europe', gateway or API

Quick Overview

CompanyRetarus Email Security
CategoryEmail Security & Anti-Phishing Software
HeadquartersMunich, Germany
FoundedNot stated by the vendor
EU PresenceEU (Germany)
Open SourceNot stated; closed-source
ComplianceGDPR-compliant (as stated by the vendor)
PricingQuoted on request; not published
Free OptionDemo or trial available on request; no published free tier
ReplacesProofpoint, Mimecast, Microsoft Defender for Office 365

Detailed Review

Retarus is a privately owned, independent company headquartered in Munich, Germany, that describes itself directly: "we answer to customers not investors." Its Email Security product is offered as a classic secure email gateway or as an API for Microsoft 365, and it includes advanced threat protection with sandboxing, post-delivery protection that keeps re-checking links and attachments after arrival, and email continuity for outages.

Retarus markets the product explicitly as "the comprehensive solution for email security made in Europe" and states its infrastructure is 100% GDPR compliant. Email security is one line in a broader Retarus messaging portfolio that also includes fax and SMS services, rather than the company's sole focus.

What Retarus does well

  • Post-delivery protection keeps checking links and attachments after they arrive, catching threats weaponized later
  • API deployment option for Microsoft 365 alongside the classic gateway
  • Privately owned and independent, marketed explicitly as "made in Europe" with 100% GDPR-compliant infrastructure

Where Retarus falls short

  • Pricing is quote-only
  • Email security is one product line within a broader messaging portfolio (fax, SMS) rather than the company's sole focus
  • Less brand recognition outside German-speaking Europe than the larger US gateways

Standout feature. Post-delivery protection that keeps re-checking links and attachments after arrival, on infrastructure marketed as 100% GDPR compliant.

Pros and Cons

Pros

  • Own self-operated data centres rather than a hyperscaler underneath
  • Processing location selectable per customer and written into the contract
  • Certified Senders Alliance, plus documentation against HIPAA, SOX, PCI DSS and TISAX
  • Guaranteed throughput rates, which matters when a queue costs money
  • German company, 33 years in business, with an enterprise support organisation

Cons

  • Data centres include the United States and APAC — European processing must be specified
  • No published pricing, no free tier and no trial
  • Sales-led onboarding rather than an API key and a card
  • Overkill for anyone sending under a few million messages a month

Alternatives to Retarus

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Frequently Asked Questions

What is Retarus?

Retarus is privately owned Munich vendor marketed explicitly as email security 'made in Europe', gateway or API.

Where is Retarus based?

Retarus is headquartered in Munich, Germany.

What does Retarus cost?

Quoted on request; not published.

Who is Retarus best for?

Post-delivery protection that keeps re-checking links and attachments after arrival, on infrastructure marketed as 100% GDPR compliant.

Is Retarus a good alternative to Proofpoint or Mimecast?

Retarus is built as a genuinely European alternative to US and UK email security vendors like Proofpoint and Mimecast. It will not be a like-for-like feature match in every respect, so check the review above for where it genuinely differs before switching.

How does Retarus compare to other Email Security & Anti-Phishing Software tools?

Retarus is one of several European email security tools covered on this site. See the full Email Security & Anti-Phishing Software category page for how it ranks against its closest European competitors.

Who worked on this review

Three people touch every tool page: one writes it, a second edits it, and a third checks the compliance and pricing claims against the vendor's own documentation.

Sebastiaan Smits
Written by

Sebastiaan Smits

Founder & Editor · Netherlands

Selects the tools, writes the reviews, and checks where each company is actually established.

Marta Kowalczyk
Edited by

Marta Kowalczyk

Senior Analyst, Infrastructure & Developer Tools · Warsaw, Poland

Covers hosting, developer tooling and the practical side of moving workloads to European providers.

Ingrid Halvorsen
Fact-checked by

Ingrid Halvorsen

Managing Editor · Oslo, Norway

Runs the review process and decides when a page is ready to publish or needs another pass.

Read our editorial process for how we source, verify and update these pages — and how we keep affiliate income separate from what we recommend.

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