SMTP. It stands for Simple Mail Transfer Protocol. But to many of us it’s far from simple, it’s another vaguely understood jargon phrase (I know it was for me before I joined Mailjet). SMTP is actually part of a technology many of you are using today on a regular basis.

What is SMTP Relay?

In normal human terms, SMTP is a basic protocol that allows email to be transmitted through the internet. It’s the post office of the web, it collects email from the sender and delivers it to the recipient’s local post office, another SMTP server.It was first created in 1982 and continues to be the internet standard that is widely used today.

To break this down a bit more, let’s imagine the journey that your normal snail mail may take to get to its destination:

snail mail

Sending through an email service provider

So what does this protocol look like when it comes to an email service provider like Mailjet? Businesses that need to send mass email to their customers use SMTP relay for ease of maintenance and added analytics insights.

Sending through an email service provider, via an SMTP relay saves companies from having to run their own mail server. As you can see in the diagram below, the business or sender creates the email and their server sends it to Mailjet’s SMTP server to prepare and send it out to recipients.

Smtp relay

A majority of webmail providers (i.e. Gmail, Hotmail, Yahoo etc) put a limit on how many you can send to different recipients per day to combat spam. As businesses would often exceed this limit, they will require the services of an enterprise level email sending platform. An SMTP relay provider can help businesses and organisations deliver large volumes of email without getting them mislabeled as SPAM.

Email service providers like Mailjet, invest a lot of resources into building their own email infrastructure to handle large volume loads and work closely with the major internet service providers and webmail providers to deliver these emails straight to the recipients inbox.

Behind the scenes tracking

There’s an added layer of value to sending through an email service provider. With Mailjet, before our SMTP servers send an email, our system automatically adds link trackers in the body of your message. This then allows you as the user to properly track opens and clicks after an email has been received.

Mailjet also translates feedback from ISPs (Gmail, Yahoo, AOL etc.), since each one communicates in its own way. Our service saves developers time by converting this into an easily identifiable response, displaying whether an email has either soft bounced or hard bounced.

A soft bounce would be if the server receiving server was down or full, a hard bounce is if the recipient’s email address is no longer active or mistyped.

Ultimately, SMTP relay makes our lives as marketers much simpler, by handling all of the heavy lifting in the backend so that we can spend more time crafting content and building out our contact lists.