The primary function of an SMTP relay service is to provide a method for email senders to access the Internet when they do not have their own IP address or when the IP address they have does not meet the IP reputation requirements of most major ISPs. A sender with such limitations needs to use an underlying service such as an SMTP relay service to transport their email.

When should I use an SMTP Relay Service?
Sending an email is simple. As long as you have access to an SMTP server, you should be able to send email anywhere in the world. That's what sets Proton Mail apart from existing email providers. Our servers do not need to go through the same type of rigorous screening that is done by larger providers like Gmail or Yahoo to gain full access to their servers.

A SMTP server is an Internet-based application that uses the Simple Mail Transfer Protocol (SMTP) to transfer email messages between servers. An SMTP server functions as an email router for incoming and outgoing mail servers. An SMTP server accepts email messages from another server or client, if necessary relays the message to another server or client, and delivers the message to the intended recipient's mailbox.

If you use a business or person-to-person-email service such as Gmail, Yahoo Mail, Hotmail/Outlook, etc. to send out bulk emails, marketing messages, and triggered person to person emails (e.g., flight delay change notification), SMTP can be used as an alternative method to deliver such emails. The message is sent through the email provider's SMTP servers and not directly from your computer. This process can be useful because it acts as a middleman between the sender and recipient and adds another step between them: this makes you less vulnerable to security risks.

Even your favorite software applications probably use SMTP to deliver transactional messages like password resets, order receipts, and other time-critical email like paycheck notifications. SMTP is used in an environment where mail clients are separate from the e-mail servers. It's used in situations where the e-mail server might be hosted by a different company or organization that doesn't have direct access to the mail client software.

Some common situations when you should send via SMTP mail relay include when:
• Email systems are now easier than ever to integrate with your ecommerce, commenting, social media…essentially anything online. For example, many email delivery providers offer users the ability to “plug it in” to send email via their blackberry device. Sending email to your customers who need an app/product is a great way to convert more sales.
• You're looking to simplify your email headaches and improve your email deliverability.
• You need an easy way to send an email or two from your hardware like a printer, scanner, fax machine, or IoT device.
• To avoid service interruptions and continue to send a high volume of email, you can use an SMTP relay provider to help you deliver email without being mislabeled as spam.
Why is using an SMTP Relay Service important?
Email is usually pretty straight forward when you’re sending simple person-to-person email . It does not require any complicated design detailed to show off amazing features. What is important is delivered within a few sentences and closing the deal.

99% of the time, managing your own email is simple. But when you need to scale up, things get a little more complex. If you’re sending marketing emails regularly, or sending time-critical notifications from your web app, it’s very likely that you’ll end up blacklisted or with a low inbox rating. In fact, you can even be labelled a spammer – triggering a very expensive and painful process of getting your domain delisted from spam lists – which may never happen.

It’s just not working out. You’re sending out transactional and marketing email from your primary server like Gmail or Exchange, and you’re experiencing deliverability issues. The solution: a dedicated email sending device (ESD) using dedicated IP addresses and built-in virus and spam protection. Let us be your virtual dedicated email service provider.

An SMTP relay service is the best way to manage batch sends and automated emails. Sending over SMTP through a trusted 3rd party will help you ensure that you don’t experience deliverability issues and that your mail keeps flowing to the inbox without any issues. You can choose from different email-delivery options:

Once you register for an Adcrux account, you’ll be able to immediately send and receive email and manage your SMTP relay and email functions in one place. Our services work with any application, and we do the hard work of making sure everything is set up and running smoothly behind the scenes. This means you can rest easy knowing your email will get delivered reliably.