SMTP
Introduction
SMTP
Introduction
Learn how to integrate Resend via SMTP.
Prerequisites
To get the most out of this guide, you’ll need to:
SMTP Credentials
When configuring your SMTP integration, you’ll need to use the following credentials:
- Host:
smtp.resend.com - Port:
25,465,587,2465, or2587 - Username:
resend - Password:
YOUR_API_KEY
Ports help to instruct the type of security you want to use in your SMTP connection.
| Type | Port | Security |
|---|---|---|
| SMTPS | 465, 2465 | Implicit SSL/TLS (Immediately connects via SSL/TLS) |
| STARTTLS | 25, 587, 2587 | Explicit SSL/TLS (First connects via plaintext, then upgrades to SSL/TLS) |
Custom Headers
If your SMTP client supports it, you can add custom headers to your emails.
Here are some common use cases for custom headers:
- Prevent threading on Gmail with the
X-Entity-Ref-IDheader - Include a shortcut for users to unsubscribe with the
List-Unsubscribeheader
FAQ
Once configured, you should be able to start sending emails via SMTP. Below are some frequently asked questions:
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