Hyvor Relay

Hosted email platforms like Resend charge recurring fees per message and retain full oversight of user data on cloud servers. Hyvor Relay runs an API-driven mail delivery engine directly on your own infrastructure, giving your applications dedicated SMTP and HTTP endpoints without metering. It combines automated deliverability workflows with direct control over outbound IP reputation.

Why Hyvor Relay instead of Resend

Resend simplifies email sending through cloud SDKs, but every outgoing notification leaves your infrastructure to travel across third-party networks. Teams sending high volumes or handling sensitive transactional records face escalating monthly bills and external data processing risks. When a vendor experiences service disruptions or changes its pricing model, your production communication pipeline is entirely exposed.

Hyvor Relay replaces third-party APIs with a self-hosted engine built with Symfony and Go. Your applications interact with internal HTTP endpoints or standard SMTP connections, keeping message contents within your private network perimeter. It automatically provisions SPF and DKIM records using an integrated authoritative DNS server, reducing domain configuration friction across client environments. In exchange, your team takes on operational responsibilities: you must configure reverse DNS with your hosting provider, monitor port 25 availability, and warm sending IP addresses manually.

What it does well

• Isolates transactional and bulk traffic into separate sending queues to protect high-priority password resets and alerts from promotional volume.
• Automates domain authentication via an internal DNS server that issues DKIM, SPF, and MX records without manual registrar editing.
• Retains complete thirty-day SMTP conversation transcripts in the management console for fast debugging of connection timeouts and mailbox rejections.
• Exports Prometheus metrics and prebuilt Grafana dashboards to monitor delivery latency, queue depths, and failure trends inside existing telemetry stacks.
• Provides multi-tenant workspace isolation with scoped API keys, enabling agencies and platform teams to manage multiple client domains on one host.
• Handles bounces, greylisting retries, and ISP feedback loops automatically to purge invalid recipients before they harm deliverability.