An email relay service is a system that sends outgoing emails on your behalf by routing them through a trusted third-party mail server instead of sending them directly from your own server or application. It acts as a middleman between your website, app, or email client and the recipient’s inbox, ensuring emails are delivered securely, reliably, and with a much higher chance of reaching the inbox rather than spam.

How an Email Relay Service Works

At a basic level, an email relay service handles the “sending” part of email delivery.

Here’s a simplified flow:

1. Your website, app, or email client creates an email

2. Instead of sending it directly to the recipient’s mail server, it sends it to the email relay service

3. The relay service authenticates the email

4. The relay service delivers the email to the recipient’s server using trusted infrastructure

Because relay services have established reputations, proper authentication, and optimized servers, emails are far more likely to be delivered successfully.

Read More: What Is an Email Relay Service?