11 Best SMTP Email Relay Services Ready to Serve You in 2024

Unlike other types of digital marketing, email marketing can get quite technical, especially if you plan on sending transactional emails or thousands of emails per day. Let’s take Facebook marketing, another great communication channel for businesses, as an example. Basically all you need to do is create a Facebook post or ad and post it. While it comes with its own unique challenges and considerations like changing algorithms, you don’t have to worry about deliverability. Sure, your post might get reported as spam, but that’s unlikely.

When sending email messages, though, you need to factor email deliverability into the planning. It’s not a given that your emails will make it to the inbox. It might get blocked directly by Gmail and other ISPs or get flagged as spam.

To prevent this from happening, you need a reliable SMTP provider in your tech stack. Here’s a quick look at what it entails and 11 email relay service providers that high-volume senders can try.

Top SMTP Email Relay Services


smtp email relay services


Brevo is one of the top email marketing software solutions and can also help with SMS marketing, WhatsApp campaigns, and live chat on top of email marketing. It guarantees a deliverability rate of 97% which is backed up by 10 years of deliverability expertise.

Similarly to SendPulse, Brevo also lets you buy email credits. This makes it a great choice for growing brands looking to stretch their marketing budgets.

In addition to SMTP relay, Brevo also offers various other setup options like email API, webhook, or plugin. Plus, it also integrates with all the main eCommerce platforms and CMS tools, making it even more versatile.

Here’s what else you can expect:

  • Shared IPs that are monitored closely
  • A rigorous validation process
  • Seasoned email deliverability specialists
  • Unlimited log retention

Plans and pricing: Brevo offers a free SMTP server for up to 300 emails per day. Pricing for transactional emails is based on monthly email volume and starts at $25 per month for up to 20,000 emails.


SMTP is one of the best email relay and deliverability providers and can help you to send a volume of email without breaking the bank or your email rep. As they like to put it on their website — they’re “engineered for reliable delivery at scale”.

To give you a better idea of just how powerful and popular this tool is, here are some key numbers:

  • SMTP sends billions of emails on a monthly basis.
  • SMTP’s ROI can be as much as 300% higher than the ROI offered by other deliverability providers.
  • They offer an uptime of 99% and a delivery rate of 98%.
  • They’ve been in the business for over 20 years.

It achieves its stellar delivery rate by proactively screening for spam. Not only do they prioritize ISP relations, but they also ensure that their email relay infrastructure keeps up with ISP protocols and benchmarks.

Plans and pricing: After a generous 30-day free trial, pricing starts at $25 per month for up to 50,000 monthly emails.


Omnisend stands as a dynamic platform at the forefront of SMTP Email Relay Services. It distinguishes itself through its mastery of email and SMS marketing, characterized by customizable templates, a user-friendly interface, and a rich array of innovative features. Omnisend empowers businesses not only to amass subscribers but also to engage customers through bespoke email and SMS campaigns, fostering lasting connections.

Omnisend has been the driving force behind successful collaborations with notable brands like Amundsen Sports, Snatcher, Inglot, SM Global Shop, and many others. These collaborations have yielded remarkable results, showcasing the platform’s capabilities in enhancing marketing strategies.

Delving into its standout offerings:

  • Email Marketing Excellence
  • Integrated SMS Messaging
  • Cost Efficiency
  • Powerful Automation
  • Precise Segmentation
  • Seamless Integration
  • Exceptional Customer Suppor
  • Data-Driven Insights

Plans and pricing: Omnisend offers a variety of pricing plans to suit different needs, including the “EMAIL + SMS Pro” plan at $59 per month for high-volume senders, the “EMAIL Standard” plan at $16 per month for growing businesses, and a free plan for beginners.


With SendPulse’s SMTP service, you can send transactional emails from your website. Then, to stay up to speed with the performance of your email marketing campaigns, you can also check SMTP stats in the mailing history. Here, you’ll find info like the number of emails sent, opens, delivery rate, bounces, and unsubscribe rate presented in an easy-to-digest graph which can also be exported as a report in CSV format.

While it’s a powerful email marketing tool (and the hundreds of online reviews SendPulse has received are evidence of that), it can do so much more. Included in its products are SMS campaigns, a chatbot builder, and landing pages.

However, if you just want to stick to email marketing (for now, at least). Here are some of the other key features that you can put to good use:

  • Subscription forms
  • Email templates
  • A drag-and-drop builder
  • A built-in spam checker

Plans and pricing: SendPulse offers a number of subscription plans as well as pay-as-you-go pricing. There’s also a free plan for users with up to 500 subscribers. Even if you don’t qualify for the free plan, pricing starts at only $8 per month which makes it one of the most affordable solutions. With the pay-as-you-go option, you’re looking at about $0.0032 per email.

SendGrid by Twilio

Trusted by a number of names in the sharing economy like Airbnb and Uber, SendGrid helps its users to send over 100 billion emails on a monthly basis. You can either plug into their SMTP relay for standardized sending or improve your SMTP relay sending with their SMTP API.

As you would expect of one of the more established players in transactional email software, in addition to offering reliable email delivery, it also offers various other useful products to help you grow and improve your email marketing campaigns. These include:

  • Template designs
  • Signup forms
  • Email automation
  • Statistics

One of the features that make SendGrid such a popular option is its level of support. Not only does it equip your marketing team with the communication tools, but it can also complement your in-house team. They offer set-up assistance as well as ongoing consulting. Together their team boasts 130+ years in email, so you’ll be able to access a wealth of strategic advice and quick answers for any deliverability issues that might pop up.

Plans and pricing: SendGrid offers a free plan, two subscription options, and custom pricing. Pricing starts at $20 per month.

Amazon SES

Amazon has become more than just an online marketplace. From affiliate programs to various solutions for advertising and marketing, it can help you to drive more revenue in more ways than one.

For help specifically with email marketing, you can check out Amazon Simple Email Service (aka Amazon SES). You can use its SMTP interface or API to send emails. It offers various SMTP-enabled programming languages.

Then, to help you keep track of your email campaigns’ performance, it includes features like:

  • A virtual deliverability manager
  • Insights, suggestions, and automatic implementation of email deliverability improvements

Whether you want to send bulk emails or timely shipping notifications to customers, it can be used for a number of use cases. Duolingo, one of the leading education apps in the world, has used Amazon SES to send daily exercises or newsletters for over a decade. In addition to its ability to send huge volumes of emails, what attracted Duolingo to Amazon SES is that it easily integrates with the other AWS solutions. It’s this level of flexibility that has also helped them to land clients like Netflix.

Plans and pricing: Amazon SES offers a very flexible pricing structure and doesn’t charge a fixed monthly contract, Instead, you pay only for what you use. Pricing starts at $0.10 per 1,000 emails. There are also a number of paid add-ons that you can check out.


It doesn’t matter if you’re running a bootstrapped startup or an agency with multiple clients, Postmark, created by ActiveCampaign, one of the best email marketing software platforms can come in handy. Included in its list of features is an SMTP service and supports TLS for data security. Not only is it secure, but also fast. As it’s a globally distributed SMTP service with endpoints in various regions, the latency is very low.

A standout feature is that you don’t have to pay extra to ensure great deliverability. One way that it does that is to vet all new senders carefully to eliminate any potential spammers. This means that even without a dedicated IP address, you can still enjoy the same level of deliverability. Combine this with their effort to keep transactional and promotional messages separate with message streams and you can enjoy peace of mind knowing that your emails will reach the right destination.

If you do get stuck though, it also includes:

  • Troubleshooting tools
  • A library with guides, open source projects, and other helpful docs
  • Great email support (they typically respond within three hours to emails)

Plans and pricing: Postmark offers a free trial (no credit card required) that includes SMTP and REST API. Pricing starts at about $15 per month for up to 10,000 monthly emails. For DMARC monitoring and dedicated IPs, you’re looking at about $10 and $50 per month extra respectively.


Thanks to its pricing and long free trial, Moosend is a great tool for small businesses. While its SMTP server isn’t included in the free trial, with pricing starting at less than $10 per month, it’s still one of the most affordable plans on the market.

In addition to its cost-effectiveness, another standout feature is that it includes reporting and analytics that you can use to keep track of how your transactional campaigns sent by means of their SMTP service performs. In fact, according to G2, its reporting has been rated as well above average.

Other features that Moosend users have praised are its:

  • Performance and reliability
  • Drip campaigns
  • Event-triggered actions
  • List management
  • Customer support

Plans and pricing: Moosend offers a free 30-day trial (no credit card required). Pricing starts at only $9 per month for up to 500 subscribers. An enterprise plan is also available.


Used by more than 150,000 developers and companies that include leading names in email marketing like Omnisend, Mailgun has established itself as one of the biggest transactional email software solutions. Its industry-leading SMTP relay services means that businesses don’t have to manage their own mail servers to send transactional as well as promotional emails. Not only does this free up time, but also reduces costs.

All you need to do is add and authenticate your domain name and Mailgun will share all the key details inside your account. If your email volume should increase, you can also switch over to their email API to speed up processes. In fact, their mail send API has been rated well above average.

As for support, they can connect you with a Technical Account Manager who’ll be able to offer recommendations and offer a helping hand. Alternatively, you can also turn to their log retention and analytics allowing you to track every step of the email journey and measure engagement.

Users have also praise Mailgun for its:

  • Intuitiveness
  • User-friendly dashboard
  • Value for money
  • Performance and reliability

Plans and pricing: Mailgun offers a free trial for one month during which you can send up to 5,000 emails. Pricing starts at $35 per month for up to 50,000 emails. Custom pricing for an enterprise-grade solution is also available upon request.


Mailjet offers a free SMTP server that’s simple to set up and integrates with any system. Basically, the only action that you need to take is update your SMTP server setting with the credentials they provide so that their server is used as a “smarthost” or “relay”. However, if you should get stuck, rest assured that their multi-lingual support team of deliverability specialists is at hand to guide during all the different phases.

Not only is it intuitive, but it also offers flexibility and supports a selection of ports. And, its versatility doesn’t stop there. Another advantage of using Mailjet’s SMTP servers is that link trackers get added automatically enabling you to monitor opens and clicks efficiently.

In addition to its outstanding sender reputation and reliability, Mailjet users have also highlighted the following as some of its biggest features and perks:

  • Email monitoring
  • Surveys
  • Integrations

Plans and pricing: Mailjet offers a free forever plan that lets you send up to​​ 6,000 monthly emails (capped at 200 per day). Pricing starts at $15 per month for up to 15,000 emails and has no daily sending limit. Custom pricing is also available.


If you don’t want to expand your focus to email marketing and simply need a tool to help with email sending and testing, you can check out Mailtrap, one of the top email testing tools. Trusted by individual users as well as businesses that include names like PayPal, Calendly, and Adobe.

Mailtrap offers a number of powerful features and tools that include:

  • Emails preview
  • A spam checker
  • Dedicated IPs

If you’re just interested in its SMTP service, you can look forward to high deliverability rates, in-depth analytics, and deliverability alerts. You can also inspect your configuration by sending a test email first.

All in all, it’s very easy to use thanks to its intuitive interface. To set up your SMTP server, no prior experience is needed. All you basically do is copy and paste the credentials.

Plans and pricing: Mailtrap offers a number of pricing plans for email testing and sending. Pricing starts at about $10 per month for up to 10,000 emails. It also includes a free plan that you use to send emails by means of SMTP or API.

What’s an SMTP Email Relay Service?

SMTP is short for simple mail transport protocol. It basically lets businesses use a separate domain and email server so that they can send emails at scale without having to worry about the dreaded spam filters.

Not only is this important for marketing purposes, but also internal communication. If businesses were to use their own servers or domain for thousands of marketing emails and the domain or server got blacklisted, even internal emails sent from one employee to another could get mislabeled as spam. Sure, if your employees were mostly using email to send funny cat memes, this would probably just hurt office morale and not productivity.

Whichever way you use email, you need a reliable SMTP relay provider. Not only is it critical for email deliverability, but it can also offer many other benefits like unsubscribe features, tracking, and analytics as the following tools illustrate.

About the Author

Koba Molenaar


Koba Molenaar brings nearly a decade of rich experience in content writing, specializing in digital marketing, branding, SaaS, and eCommerce. Her passion for helping brands, from solopreneurs to established companies, connect with their audiences shines through her work. As a member of the Golden Key International Honor Society, Koba’s commitment to excellence is evident in her work, showcasing her as a relatable and knowledgeable voice in the industry.


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