Email Guide
What is an SMTP relay?
An SMTP relay sends outbound mail on your behalf, improving deliverability and working around ISP or network restrictions.
When you need an SMTP relay
- Your ISP blocks outbound port 25.
- Your server's IP reputation is new or inconsistent.
- You want consistent authentication and logging for outbound email.
- You need a smart host for Exchange, Postfix, apps, or devices.
How it works (high level)
Your application connects to the relay server using SMTP with authentication (username/password). The relay then delivers mail to recipients using its outbound infrastructure.