Emails have become the primary mode of communication in the 21st century, and naturally, businesses are mostly dependent on emails for their day-to-day functioning. Our growing uses and requirements mandate a more versatile email system and the addition of more tools to the standard platforms. |

The regular email service providers cannot always meet these demands, leading to other independent service providers fulfilling the roles. One such tool that significantly enhances the function of emails is the Simple Mail Transfer Protocol (SMTP).

What Are The SMTP Service And SMTP Relay Service?

Before we talk about the functions, benefits, and other aspects of the SMTP relay service, it is first necessary to understand what exactly SMTP and email relay services are.

In an email service, you send an email to someone and receive one from others. Now, some specific services or protocols make the sending and receiving of emails possible. Protocols like IMAP and POP allows you to receive emails from a mail server, and the protocol that enables you to send emails through a mail server is SMTP. So, to send an email to others, you need is SMTP service.

The term relay service, much like its implication in the sport of relay race, refers to the handing of emails from point to point. It relays the email content from the sender’s server to that of the receiver and ensures its delivery to the end receiver. To put it in simple terms, just like the relay runners in a team pass on the baton from one member to the other as they progress towards the end line, so also are emails exchanged between the servers of the sender and the receiver. SMTP Relay Service is a service that takes care of the channeling of the emails from the sender to the receiver. It channels the emails via trusted third-party service providers to deliver the bulk business emails of the sender to the target receivers.

SMTP service ensures that the outgoing mails of an organization reach their destined inboxes, and they also see to it that no incoming emails are accepted. SMTP is the system that helps a company send, receive, and relay messages between their many associations.

Now, you may be wondering about why businesses need such services while we can send and receive emails with standard email clients like Gmail and Yahoo Mail. We will come to that in a while.

MORE: Smtp Service Windows

Reasons To Get SMTP Relay Service For Your Business

Managing your emails on standard email clients is an easy task when you only have to deal with personal emails. The process becomes complicated when you operate a business that has to send their business-related emails efficiently and regularly. For example, an organization may need to send time-critical messages from their websites or web apps, or it periodically sends marketing emails to thousands of people at a time. In such situations, a primary email platform like Gmail, with their per-day limits, usually causes deliverability issues.

Another problem with primary email clients is that most of your marketing emails will land up in the spam folders of your recipients and not in their inboxes. And you cannot ensure avoidance of this. You can make sure that your emails find their way into the mailboxes of your targets with dedicated SMTP relay services.

Here are five more reasons you should consider getting an SMTP Relay Service for your business:

  • Getting a carefully weighed SMTP Relay Service is a one-time investment relieving you from subsequent expenses.
  • It saves a lot of precious working time that can be used for other work instead.
  • There is no need to worry about the non-delivery of emails.
  • The entire thousands of people on your receivers’ list are sure to receive their copy of the email without the need for any manual intervention.
  • It ensures that outgoing emails do not get marked as spam, and also that no unnecessary incoming emails spam your inbox.

List Of The Best SMTP Servers For You

We have listed the most convenient and preferred SMTP service providers below to help you make a wise decision and a profitable investment for your business. Though it is not entirely a free SMTP Server list, all the providers listed have free versions or free-trial periods. This gives investment-free options for startups and those on a low budget.


This is a suitable option not just for Windows users but also for everyone in general as it has an excellent reputation for maximizing the delivery rate of emails. Its customer service is active 24/7, and it has the following advantages:

  • It makes use of reliable IPs.
  • It ensures fast and swift delivery of emails.
  • It ensures zero identification by email filters.
  • It comes with a useful and accurate email tracking system.

TurboSMTP comes with a free 6,000 relay emails per month scheme. You can choose a suitable plan for yourself if your requirements exceed the number of emails offered in the free program.


Mailgun is a good option for fast delivery and traceability of sent emails. It also comes with an inbuilt HTTP API and other features like the routing of spam into its filterMailgun is one of the preferable options because:

  • It provides several products, such as SMTP reputation check, transactional SMTP, and SMTP API, etc.
  • It comes with solutions like SMTP bulk email service, free SMTP service, and transactional email services.
  • It also includes use cases such as free open SMTP relay, transactional email API, the email service for developers, etc.

Customers can avail the free trial of Mailgun and then choose a monthly plan based on their monthly emails and validation requirements.


With over 80,000 users, Sendgrid handles over 50 billion emails every month. It is a reliable option for SMTP services, and you can use it under the free trial option or its various paid schemes. It provides real-time, customizable analytics, global support, scalable infrastructure, and industry-leading deliverability, which all combine to make it one of the best choices.


MailChannels is a suitable option for businesses as it is cost-effective and time-efficient. It is very reliable and is a trusted choice of thousands of users. It boasts of providing 24×7 email support and takes 20 minutes at max to respond to customers’ grievances. They ensure excellent email deliverability and include both free trials and paid schemes.


Another option popular and reputed SMTP service available is MailJet. It provides free SMTP services which are very practical and easy to incorporate into your existing systems. All you need to do to start using the service is updating your configuration via the MailJet SMTP server through one of the supported ports and authenticating it with your credentials (API key, secret key).

Google SMTP Server

This SMTP server comes with Google’s Gmail, and all those with a Gmail account can use it for their various needs, such as sending emails containing contact forms, newsletter blasts, or notifications. Google SMTP server is a free service but is, however, subject to a few requirements:

  • The server required for outgoing mail is
  • The setting for “Use Authentication” must be set to yes.
  • The setting for “Use Secure Connection” must be set to yes.
  • The username by default is the one you use for your Gmail account.
  • The password is auto-set to be your Gmail password.
  • The port required is either 465 (SSL required) or 587 (TLS required).

Compatibility is seldom a big issue when it comes to SMTP services. However, when making your selection of an SMTP service, Windows compatibility, Mac compatibility, or the service compatibility to your existing systems and platforms should be kept in mind.