Smtp mail relay
Published November 4, 2024 · Updated July 21, 2026 · SMTP & Deliverability
An SMTP mail relay is the middle-man that takes an email from one server and passes it along to its destination. It sounds simple, but relays are the quiet backbone of business email — letting apps, devices, and websites send mail reliably through a single trusted point. Here is what an SMTP mail relay is, when you need one, and how to choose a good one.
What an SMTP mail relay does
Instead of every app and device figuring out how to deliver mail on its own, they hand it to a relay. The relay authenticates the sender, applies the right IP and DKIM signature, and delivers to the recipient's server. One central relay means consistent authentication, better deliverability, and easier management.
When you need a mail relay
- Apps and websites that send notifications, receipts, or password resets.
- Devices like printers and scanners that email documents.
- Bulk and marketing sends that need a dedicated IP and volume.
- Multiple systems that should all send through one authenticated point.
A dedicated SMTP mail relay for your business
Dedicated IP, unlimited throughput, and automatic authentication — route every app, device, and campaign through one reliable relay. From $39.99/mo.
Frequently asked questions
What is an SMTP mail relay?
A server that accepts email from your apps or devices and forwards it to recipients, applying authentication and IP reputation so the mail is delivered reliably.
Do I need an SMTP relay?
If apps, devices, or websites send email — or you send in volume — a relay centralises delivery and improves deliverability. A dedicated relay adds your own IP and unlimited throughput.
Is a mail relay the same as an SMTP server?
Closely related — a relay is an SMTP server whose job is to accept and forward mail. A dedicated SMTP service acts as your relay with a dedicated IP and full authentication.