Hyvor Relay is a self-hosted, open-source email API for developers. It uses SMTP to send emails using your own infrastructure. It is designed to be simple to self-host, easy to manage and observe, and powerful enough to send millions of daily emails.
Email API for Developers | Self-Hosting Docs | Product Docs
- Self-Hosted: Docker compose or swarm-based deployment.
- Health Checks: Multiple health checks to ensure best performance and deliverability.
- Email API: Send emails using a simple API.
- Logs & SMTP Conversations: View send logs and SMTP conversations of sent emails up to 30 days.
- Multi-Tenancy: Support for multiple tenants with scoped access (useful for organizations and agencies).
- Project Management: Support for multiple isolated projects within a tenant.
- Queues: Two main queues to isolate transactional and distributional emails and IP reputation.
- Greylisting & Retries Handling: Automatically manage greylisting and retries.
- Bounce Handling: Automatically handle bounced emails.
- Feedback Loops: Integrate with feedback loops to manage spam complaints.
- Suppressions: Automatically manage email suppressions (bounces, unsubscribes, etc.).
- DNS Automation: Delegate DNS to the in-built DNS server. No need to manage DNS records manually.
- Webhooks: Receive HTTP callbacks for email events.
- Easy scaling: Add more servers and IP addresses as needed.
- Observability: Prometheus metrics, Grafana dashboards, and logs for monitoring.
The sudo dashboard for admins:
The console for users (viewing send logs and SMTP conversations):
- PHP + Symfony for the API backend.
- Go for email workers, webhook handlers, DNS server, and the incoming SMTP server.
- SvelteKit and Hyvor Design System for the frontend.
- PGSQL is used for the database as well as for the queue.
- Roadmap
- HYVOR Community (best for discussions and support)
- Discord (best for latest updates)
Visit hyvor/dev to set up the HYVOR development environment. Then, run ./run relay to start Hyvor Relay at https://relay.hyvor.localhost.
Directory structure:
/backend: Symfony API backend/frontend: SvelteKit frontend/worker: Go services (single binary)
Even though it is written for AI agents, AGENTS.md contains useful information on the project structure and development practices.
Hyvor Relay is licensed under the AGPL-3.0 License. For use cases that cannot comply with AGPLv3, contact HYVOR for an Enterprise License.
Copyright © HYVOR. HYVOR name and logo are trademarks of HYVOR, SARL.