Hyvor Relay: Open-Source Self-Hosted Email API for Developers

Hyvor Relay: Open-Source Self-Hosted Email API for Developers

Summary

Hyvor Relay is an open-source, self-hosted email API designed for developers, offering a robust alternative to services like AWS SES, Mailgun, and SendGrid. It enables sending emails via SMTP using your own infrastructure, prioritizing ease of self-hosting, efficient management, and scalability for high-volume email operations.

Repository Info

Updated on May 28, 2026
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Tags

emailsmtpphpself-hostedemail-apiopen-sourcedeveloper-tools

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Introduction

Hyvor Relay is a powerful, open-source email API for developers, designed as a self-hosted alternative to popular services such as AWS SES, Mailgun, and SendGrid. It allows you to send emails using your own infrastructure via SMTP, giving you full control over your email delivery. The project emphasizes simplicity in self-hosting, ease of management and observation, and the capability to handle millions of daily emails efficiently.

Key features include a comprehensive Email API, detailed send logs and SMTP conversations, multi-tenancy support, project management, dedicated queues for different email types, automatic handling of greylisting, retries, and bounces, and integration with feedback loops. It also offers DNS automation, webhooks for email events, easy scaling, and robust observability through Prometheus metrics and Grafana dashboards.

Installation

Setting up Hyvor Relay is streamlined for developers. The project supports Docker Compose or Swarm-based deployments, making it straightforward to get started. For development purposes, you can leverage the hyvor/dev environment.

To set up the HYVOR development environment, visit hyvor/dev and follow the instructions. Once configured, you can run ./run relay to start Hyvor Relay locally at https://relay.hyvor.localhost.

Examples

Hyvor Relay provides a simple yet powerful API for sending emails programmatically. Developers can integrate this API into their applications to manage both transactional and marketing email campaigns effectively.

Beyond sending, the platform offers a user-friendly console where you can view detailed send logs and full SMTP conversations for emails sent up to 30 days. This feature is invaluable for debugging, monitoring email delivery status, and ensuring optimal performance.

Why Use Hyvor Relay?

Choosing Hyvor Relay offers several compelling advantages for developers and organizations:

  • Self-Hosted Control: Gain complete control over your email infrastructure, data, and privacy by hosting it on your own servers. This eliminates reliance on third-party vendors and their pricing models.
  • Open-Source Transparency: Benefit from the transparency and flexibility of an open-source solution. The community can contribute, audit the code, and adapt it to specific needs.
  • Feature-Rich: From advanced queue management to automatic bounce and suppression handling, DNS automation, and webhooks, Hyvor Relay provides a comprehensive suite of features essential for modern email delivery.
  • Scalability and Performance: Built to handle high volumes, it allows for easy scaling by adding more servers and IP addresses as your needs grow, ensuring consistent performance and deliverability.
  • Observability: Integrated Prometheus metrics, Grafana dashboards, and detailed logs provide deep insights into your email operations, helping you monitor health, performance, and troubleshoot issues proactively.
  • Cost-Effective Alternative: Reduce operational costs associated with commercial email services while maintaining a high level of functionality and reliability.

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