EmailSuccess vs Posthawk

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.

Posthawk has no write-up on Specifiction yet; its figures are above.