Retarus Transactional Email: Fast, Reliable, and Secure
We offer guaranteed throughput rates, first-class inbox placement, and increased customer engagement through our reliable transactional email delivery.
Schedule a demoReta cares about email delivery!
98% + delivery rates and unlimited capacity! Scale your business and reduce latency. No more waiting for emails!
High Performance
Send high volumes of emails via API from your business applications with contractually guaranteed throughput rates without straining your own infrastructure.
Improve Your Reputation
Retarus is a leader in reputation management and CSA (Certified Senders Alliance) certified. We protect your domain, IP reputation and sender score.
Get The Most Out Of Your Email
Our comprehensive APIs simplifies your email workflows. Outsource resource-heavy capabilities like Templating, Sanitization, Optimizations, Rendering and more.
Expansive Compliance and Certifications
Adhere to local data protection regulations and 100% GDPR-compliance. We process data in self-operated data centers in Germany, Switzerland, US, or Asia.
Retarus Transactional Email Data Flow
- SMTP Basic authentication
- SMTP Source IP authentication
- REST Basic authentication
- DMARC
- DKIM
- SPF
- Unsubscribe list
- Suppression list
- Bounce management
- CSA Certified IPs
- Template rendering
- Address rewriting
- Trace and Recover
- Campaign support
- Anti virus multiscan
- Message signing
- Secure document handling
- 3rd party archiving
- Spam Score Check Report
- Feedback Loop Reporting
- Open-/Link Tracking
- Bounce Reporting / Response Manager
- Trace and Recover
- web-based myEAS portal
- Self-service capabilities
- SMTP Basic authentication
- SMTP Source IP authentication
- REST Basic authentication
- DMARC
- DKIM
- SPF
- Unsubscribe list
- Suppression list
- Bounce management
- CSA Certified IPs
- Template rendering
- Address rewriting
- Trace and Recover
- Campaign support
- Anti virus multiscan
- Message signing
- Secure document handling
- 3rd party archiving
- Spam Score Check Report
- Feedback Loop Reporting
- Open-/Link Tracking
- Bounce Reporting / Response Manager
- Trace and Recover
- web-based myEAS portal
- Self-service capabilities
Who is Retarus Transactional Email for?
One size does not fit all. Our clients rely on Retarus for highly capable, high-volume emailing to their end customers. Whether for critical communication, increasing customer engagement, application integration, or specialized requirements.
Software Vendors, Platform Businesses
Our ideal customers are fast-growing who rely on B2C emails for confirmations, invoices, and marketing, and need flexible, dependable solutions for time-sensitive, process-driven communications. Their workflows often trigger multiple messages per customer action, making them perfect candidates for scalable, reliable email solutions.
Large Enterprises
Diverse recipients and communication preferences, complex business workflows, and high-volume demand can quickly strain email infrastructure. Enterprises need an intuitive solution, especially when their Email Infrastructure is complex with on prem, cloud, legacy, or 3rd party applications, devices, subsidiaries.
Highly Regulated Industries
Sending or receiving critical information such as invoices, order confirmations, or time-sensitive notifications cannot afford any delays or land in spam. Strict compliance regulations in sectors such as healthcare, manufacturing, retail, finance, and legal force businesses to find a reliable, secure email solution.
Customer Ratings and Reviews
“We came to the conclusion that we need a purely European supplier. Turned out, Retarus was the best. Quality of Service, EU-based. We only use Retarus. You beat 'em all!”
Read customer story Brian Schau, Head of Development, twoday A/S
“We attach great importance to complying with regulatory requirements. With Retarus, we have a multi-channel communication partner who understands what we need as a bank. We were also able to see this for ourselves in an in-depth audit.”
Read customer story Carsten Hoffmann, Operational Manager, DZ Bank AG
“The Beth Israel Lahey Health System was challenged with several outdated faxing systems and a significant failure rate with a high TCO, leading us to look for a secure, consolidated, cloud-based solution with Epic integration. [...] Not only have we saved millions of dollars associated with faxing services, but we also reduced the failure rates which resulted in overall operational efficiency.”
Read customer story James Roeber, Director of Infrastructure Solutions, Beth Israel Lahey Health System
“Retarus Enterprise SMS has been running reliably for years – and whenever we have a question, support responds quickly and competently. That kind of dependability makes all the difference.”
Read customer story Dachser
“Retarus fully meets our goal of providing a standardized fax solution that can be used worldwide and complies with legal requirements.”
Read customer story Benjamin Bönning, System Consultant Communication, B. Braun Melsungen AG
Why Choose Retarus Transactional Email?
Highest Throughput Rates
Advanced Reputation Management and Beyond
- Unparalleled inbox placement (average sender score = 99, industry average is 85). Dynamic IP routing according to sender domain, CSA certification, bounce management. SPF, DKIM and DMARC implementation to maintain a high inbox placement.
- Convey trust, confirm email authenticity, and increase email acceptance with Messaging Signing.
Auditable Data Centers
- Data centers in the United States, in Europe and in the APAC region
- Retarus’ data centers are self-operated, self-sufficient, and redundant
- No hyperscalers, local data processing available
- Multi-client capability thanks to multi-domain configuration. Failover and load balancing options available
- All data centers are operated according to the latest standards and fulfill strict requirements: EU GDPR, HIPAA, Sarbanes-Oxley, or PCI DSS, CAN-SPAM, TISAX
Fast Implementation
- Our experienced team handles every detail of onboarding and go-live.
- Devoted service management makes sure you get the most out of your email.
Reporting and Administraton
Our easy-to-use myEAS web portal lets IT teams operate and configure services efficiently and precisely. With intuitive dashboards, real-time data monitoring, and in-depth reporting, garner valuable, actionable insights.
The self service area of myEAS allows IT admins to to fully manage their Transactional Email configurations independently, minimizing the need for support.
Real People, Real Support
- No call center nor chatbots
- You get experts who know what they are doing
- We become part of your team from scope, migration, production and Go-live
Transactional Email Tailored to You
Native APIs & Gateways
Easily integrate Retarus Transactional Email into existing workflows via APIs including REST and SMTP to reduce complexity and bolster your landscape.
Transactional Email for Business Applications
Retarus Transactional Email integrates directly via business applications including SAP, Microsoft, Salesforce, or ServiceNow.
Frequently Asked Questions
Where can I find out more?
Read our case studies and analyst reports. Check out our corporate blog and upcoming webinars, and feel free to book a demo. We’re always happy to help.
Is the implementation of transactional email difficult?
Not with Retarus. Enterprises often have complicated requirements or critical processes that cannot be interrupted, but we have experience from thousands of successful migrations and onboardings with many of the world’s leading companies.
Is there documentation available about compatibility and feature details?
Yes. Retarus Transactional Email supports numerous types of business applications and has a rich feature set. Detailed feature overviews and documentation can be found here.
How can AI be leveraged in Retarus API Documentation?
The Retarus Docs MCP Server allows AI tools such as Claude, Cursor, ChatGPT, and VS Code to access public Retarus documentation directly through the Model Context Protocol (MCP). Instead of relying on manually copied content, AI assistants can retrieve relevant information from the Retarus Developer Portal on demand and in context.
This helps users quickly find API endpoints, authentication requirements, parameters, example requests, reporting queries, and other documentation. It can support both developers and non-technical users when researching APIs, planning integrations, or answering documentation-related questions. For more detailed information, check out our documentation here.Is the Retarus Docs MCP Server secure?
Yes. The Retarus Docs MCP Server provides read-only access to public documentation only. It does not provide access to customer data, credentials, user accounts, or production systems, and it cannot execute API requests.
As with any AI-generated output, responses should be reviewed against the official Retarus documentation before implementation or operational use. Setup instructions and additional information are available here.