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11 Best SMTP Services for Reliable Email Marketing (Pros & Cons)

In this post, we’re going to share the pros and cons for 11 of the most popular SMTP services for reliable email marketing.

Email is an essential part of running a WordPress site, but WordPress by default uses PHP to send emails.

The problem is that a lot of shared hosting providers don’t configure PHP properly, or they’ve disabled it entirely to avoid abuse.

This means that your WordPress emails aren’t getting delivered.

SMTP services offer an easy and secure solution to this problem, but there are a ton of them on the market. That’s why we’ve done the work to narrow it down to this list of popular SMTP services.

Before we get into the list, you may be wondering what the heck SMTP is and why—or even if—you actually need it. Keep reading and we’ll answer all those questions!

What Are SMTP Services and Why do You Need One?

what is smtp

What is SMTP?

SMTP (Simple Mail Transfer Protocol) is the industry standard to send emails on the internet. It uses proper authentication that increases the likelihood that your emails will be successfully delivered to your user’s inbox.

WordPress sites rely on email for various things like:

  • Registering a new account
  • Recovering lost passwords
  • Notifications for password changes, new posts, comments, and tons of other things

For eCommerce sites, it can be even more urgent that users get their emails. After all, you’re dealing with people’s money, right? You want to make sure that things like customer order confirmations and invoices, shipping notifications, delivery confirmations, and more order-related information is getting through.

There are quite a few problems with the default mailing method WordPress uses (PHP), and it actually fails quite often.

For successful and reliable email marketing, you need to choose a high-quality SMTP service.

So, let’s take a closer look at some of the most popular SMTP services available. We’ve also included pros and cons for each of the SMTP services that we’ve seen most often reported in user reviews.

1. WP Mail SMTP

wp mail smtp

WP Mail SMTP is the best WordPress SMTP plugin and it allows you to easily send WordPress emails using any SMTP service provider. Plus, it’s super easy to set up.

It’s available as a free SMTP plugin, or you can upgrade to the pro plugin to get access to more features.

WP Mail SMTP offers easy setup for other SMTP providers like SendGrid, Mailgun, and Gmail with the free plugin; Amazon SES and Microsoft SMTP come with the Pro plugin.

And, if all of this SMTP stuff makes your head hurt, you can sign up for the Elite plan and get White Glove Setup to have an expert from their team set up your SMTP service for you.


  • Instead of having different SMTP plugins and workflows for different SMTP providers, WP Mail SMTP brings them together into one
  • Works with all major email services
  • Native Microsoft and Amazon SES integrations (Pro)
  • Full control over which email notifications WordPress sends (Pro)
  • Backed by the WPForms team


  • WordPress multi-site isn’t fully supported (though there are workarounds)

2. Mailjet


Mailjet has a robust API with an SMTP relay service and it’s consistently ranked one of the best SMTP service providers on the market.

You can easily integrate Mailjet with your website and use it to create and send email newsletters, design email marketing campaigns, as well as a transactional SMTP email service.

Mailjet also has excellent email marketing features like a drag and drop editor, email templates, and A/B testing, as well as advanced statistics so you can easily track your open rates, delivery rates, click-through rates, and more.


  • Template designer included, with the ability to upload custom templates
  • Good interface, clean and easy to understand
  • Great analytics, graphs are clear and well-organized


  • Customer service is not the greatest, slow response time

3. SendinBlue


SendinBlue is a popular email marketing service that also offers SMS marketing. And, it’s another of the top SMTP providers on the market.

This SMTP provider works great with WordPress and other marketing tools like OptinMonster, Google Analytics, and more.

SendinBlue has an extendable API and SMTP relay service that improves email delivery for transactional emails.


  • Inexpensive and competitive pricing
  • Variety of automation features for email marketing
  • Intuitive, easy-to-use interface
  • Customizable email templates


  • Support is a bit on the slow side

4. Mailgun


Mailgun is a popular SMTP service for developers. It has powerful APIs that make it easy to send, receive, and track transactional emails.

Plus, Mailgun is an easy-to-scale SMTP service. Sending marketing and transactional emails shouldn’t be a problem regardless of what type of site you’re running: eCommerce store, small consulting business, membership website, or something else entirely.


  • Incredibly powerful
  • Supports testing mode
  • Great for developers: has a RESTful API with libraries and code examples in curl, Ruby, Python, PHP, Java, C#, Go


  • Support is not excellent
  • Lacks beginner-friendly features of other SMTP providers on our list

5. SendGrid


SendGrid is a cloud-based SMTP service that lets you send and receive bulk emails without managing an SMTP server. And, you can create email marketing campaigns!

The SMTP service is easy to set up and works with any WordPress site, and offers excellent scalability.

SendGrid also provides complete analytics and real-time feedback on every email you send.

As far as email deliverability goes, SendGrid has tools that will improve it, like dedicated IP addresses and domain name authentication tools.


  • Seamless integration with WordPress via the plugin
  • Responsive—and helpful—customer support


  • Paid plans might be too pricey for new businesses

6. Amazon SES

amazon ses

Amazon SES is a flexible and scalable SMTP service for developers and marketers to send marketing, notification, and transactional emails.

This SMTP service offers high deliverability and powerful features but is mostly geared towards developers and advanced users.

Amazon SES is easy to integrate into your WordPress site with a little help from plugins (like WP Mail SMTP).

Amazon SES does one thing (deliver emails), but it does it well.


  • One of the most competitive prices on the market
  • If you’re hosting your web application on Amazon EC2, the first 62,000 emails each month are free


  • Poor error handling

7. Postmark


Postmark is one of the best SMTP services that specialize in sending transactional emails, so you just know they’re focused on email deliverability and speed.

This SMTP service provider offers excellent analytics and security, as well as mobile-friendly responsive email templates, message events that can be triggered with simple webhooks, and more.


  • Detailed analytics with 45 days worth of email logs showing emails sent, received, who received them, who read them, and who marked them as spam
  • Multiple server locations (3 in the US, 1 in Amsterdam, and 1 in Singapore)


  • One of the most expensive (if not the most expensive) SMTP services in the market
  • Postmark actively discourages the use of its services for newsletters

8. G Suite

g suite

G Suite lets you get a professional business email address while still hanging onto the familiarity of the Google interface. Plus, you get access to the entire productivity suite: calendar, Google Drive, Docs… everything you need, with your own domain.


  • Super cheap
  • Great for small businesses
  • Reliable infrastructure


  • Limited to 2000 messages/day

9. Moosend


Moosend is an affordable SMTP service that comes with a staggering 98% email deliverability rate.

This SMTP transactional email service includes a drag and drop email builder that makes it super easy to design transactional emails. You can also create and send an email blast and track the emails in real-time.


  • Affordable plans
  • Simple and easy to use A/B testing options
  • Great customer support
  • Advanced list of segmentation tools


  • The free plan has Moosend branding

10. Mandrill

mandrill by mailchimp

Mandrill is the SMTP service created by Mailchimp. It’s a secure and efficient way to send transactional emails if you’re a Mailchimp user.

You can also use Mandrill to send your email marketing and eCommerce emails. Plus, Mandrill has advanced tracking so you can monitor the open rates, bounce rates, and click rates for your Mailchimp emails.


  • Easy integration with the Mailchimp platform
  • Very reliable for Mailchimp users


  • Only works with Mailchimp

11. Pepipost


Pepipost is an email API and SMTP service that provides a secure platform to send emails.

It has simple settings that make it easy to connect and send bulk emails quickly.

Pepipost keeps track of your email delivery, open rates, and bounce rates, as well as notifying you of unsubscribers and other actions taken by your users.


  • Unique payment plan: pay only for emails that are not opened (it’s up to you to make quality emails that users want to open so you pay less)
  • Simple HTTP APIs that are easy to understand and integrate
  • 24×7 support


  • While support is 24×7, it’s been reported that they don’t pay much attention to smaller businesses
  • Slow to approve new accounts
  • Unpredictable price since you never know how many users will open your emails, hard to budget

Choosing the Best SMTP Services

Aside from the top SMTP providers that we mentioned above, there are literally dozens of others like SocketLabs, MailGet, Elastic Email, and even more!

There are so many SMTP service providers out there that let you send mass emails, WordPress emails, transactional emails, and any other kind of email you can think of.

But sending emails is the easy part, right?

What’s really important when choosing an SMTP service is:

  • Email deliverability
  • Scalability
  • Budget

All of the SMTP services that we covered in this article are popular because they offer high deliverability and have great features and scalability.

So, which should your business choose? Here’s what we think…

Best SMTP Services for Small to Midsize Websites:

Best SMTP Services for Larger Websites:

There you have it! We hope you found this article about SMTP services for reliable email marketing super informative. Let us know in the comments which SMTP service you decided to go with—or if you chose another one entirely.

And don’t forget that you can always get the best marketing advice from OptinMonster by following us on YouTube, Facebook, and Twitter!

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