EmailSuccess vs Retarus Transactional Email

EmailSuccess is an on-premises mail transfer agent for enterprise email gateways and high-volume SMTP servers. It manages outbound delivery, sending reputation, and changing authentication requirements. Its deliverability engine analyzes ISP responses and adjusts delivery settings in real time. Flexible queues, multiple IP pools, and connection pooling support high-volume sending and traffic prioritization. Authentication features include DKIM signing, DMARC compliance, and SPF and SenderID monitoring; TLS delivery encryption can be governed by configurable rules. The product classifies and reports bounces and feedback loops, and can forward ISP spam complaints to another system. Sending and message analysis are supported through SMTP, input scripting and filtering, and REST and SOAP APIs. Management tools include VirtualMTA traffic segmentation, an SSH console, and a web interface for monitoring and message history. The Free plan costs nothing, billed annually, and lists 100,000 emails per day and two active IPs.

Retarus Transactional Email sends high volumes of transactional messages from business applications through Retarus Enterprise Cloud. It offers REST API and SMTP interfaces, with JSON and SMTP/MIME formats, and direct connections to SAP, Microsoft, Salesforce, and ServiceNow. Retarus reports a delivery rate of 98% or higher and guaranteed processing capacity of 100,000 emails per hour; its Email API page separately states capacity of up to 10 million per hour. Administrators can use the myEAS web portal for dashboards, real-time monitoring, reporting, and configuration. The Email API can locate outbound messages by time, message ID, sender, or recipient and provides status information for the past 45 days. Security features include SPF, DKIM, DMARC, enforced TLS, antivirus multiscan, encrypted attachments, and message signing. Retarus processes data in self-operated centers in Germany, Switzerland, the United States, and Asia. The service is paid, with pricing on request. Its free trial costs nothing for 30 days, permits up to 5,000 emails, caps processing at 200 emails per hour, and excludes load testing.