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

Are you looking for the best SMTP provider to ensure your emails are delivered?

WordPress relies on PHP to send emails but a lot of times it isn’t configured properly or disabled by hosts to avoid abuse.

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

SMTP services offer an easy and secure solution to this problem.

In this post, we’ve listed the popular SMTP services so you can pick the right one for your site.

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. 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.

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

Best SMTP Services for Email Marketing

Before you choose an SMTP service, we want to draw your attention to collecting genuine emails, signups, and registrations.

When you use an SMTP service, regardless of the type of email you send, if your contact list is filled with spam and fake addresses, you can be blacklisted. And it’s a lot of trouble to fix it!

This is where it becomes important to choose the right WordPress tool to set up your login, registration, and checkout forms. We recommend using WPForms for this.

WPForms homepage

WPForms is a drag and drop form builder that lets you create all types of forms. It comes with built-in anti-spam and captcha protection that detects spambots and blocks fake entries. It also lets you manually review and block specific addresses. So you can be sure your email list is clean.

It integrates seamlessly with popular email sending services and SMTP services like the ones we’ve mentioned below.

Now, that you know the right way to set up forms on your site, let’s take a closer look at 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.

This post includes both paid and free SMTP server providers.

1. SMTP.com

smtp homepage

SMTP.com is hands down the most powerful email delivery service on the market. Not only can it handle large volumes, but it also ensures speedy delivery.

It’s built on a highly responsive infrastructure that ensures there are no delays.

SMTP.com lets you set up, integrate, and start sending emails in minutes.

It also comes with a Reputation Defender addon to proactively monitor your email list health. It protects your domain and IP reputation and ensures high delivery rates.

SMTP.com also gives you comprehensive reports so you can check and improve your email delivery and engagement performance.

It meets the needs of businesses and developers alike and has affordable plans for all.


  • It supports shared IPs and dedicated IPs
  • Flexible and scalable plans
  • Proactively checks and blocks spam and maintains high delivery rates
  • Superfast delivery with over 99% system uptime
  • It has a highly responsive support team that’s available 24/7
  • Effortless migration from other services


  • The interface misses one or two minor features. It doesn’t stop it from being the best email sending service, but they could be helpful additions.That said, the developers are constantly innovating and improving the service. So you can reach out to their friendly support team with suggestions and they will happily consider it.


Pricing starts at $25/month.

2. WP Mail SMTP

best smtp email service wp mail smtp

WP Mail SMTP is the best WordPress SMTP plugin and it allows you to easily send WordPress emails using any SMTP email 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 mail clients 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 the best email sending services
  • Native Microsoft and Amazon SES integrations (Pro)
  • Full control over which email notifications WordPress sends (Pro)
  • Backed by the WPForms team


  • WordPress multisite isn’t fully supported (though there are workarounds)


WP Mail SMTP is a free SMTP service. However, they do offer premium versions starting at $49/year.

For more information, check out this post on how to set up SMTP for WordPress.

3. Constant Contact

constant-contact email marketing

Constant Contact is one of the most popular email marketing and SMTP services.

It comes with templates and a drag and drop builder to create stunning emails that convert. Plus, you can build your email subscriber list, manage your contacts, and track your progress.

Constant Contact is by far the most reliable email service on account of its high delivery rate of 97%.

It’s an excellent choice for beginners. Not only does it provides you with all the essential features you’ll need to grow your email list, but it also offers amazing customer support to help you resolve any issues.


  • Create high converting emails in minutes
  • Loads of integrated marketing and automation services
  • Real-time reporting and analytics
  • Advanced marketing tools such as custom web page, surveys and polls, and event management


  • While it does have advanced tools, it’s designed for beginners. So it may have fewer behavior targeting capabilities that advanced users would like.


You can use it as a free SMTP service for a month. After that, plans start at $20 per month based on the number of contacts you have.

4. Brevo (formerly Sendinblue)

Marketing Automation Tools - Brevo

Brevo (formerly Sendinblue) is a popular email marketing service that also offers SMS marketing. In short, it’s an all-in-one marketing platform that also ranks as one of the best SMTP service providers on the market.

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

Brevo has an extendable API and SMTP relay service that improves email delivery rates for transactional emails. That means more of your emails will go to your audience’s inbox rather than their spam folders.

Pricing plans are dependant on sending limits rather than the number of contacts. This gives Brevo a unique advantage for small businesses looking to scale.

The free version allows for up to 300 emails per day, which is plenty to get started. The next paid plan (Lite) starts at $25 and lets you send unlimited emails. The Enterprise plan unlocks even more features but requires you to get a quote from their sales team.


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


  • Support is a bit on the slow side


The free SMTP service plan includes 300 emails/day. Paid plans start at $25/month.

5. HubSpot

hubspot email marketing

HubSpot is a popular all-in-one marketing platform that comes with free email marketing that is easy to use, loaded with features, and has extremely high deliverability.

With HubSpot, you can pick from many drag and drop templates, or you can create a custom design from scratch. You can personalize and preview messages to make sure that each recipient is getting relevant content. And A/B tests allow you to compare different versions of an email to understand what resonates best with your audience — leading to higher opens.

This tool is a perfect choice for growing businesses that want high deliverability and a platform packed with easy-to-use features that can help improve email marketing performance.


  • Easy to create stunning emails from pre-built templates or from scratch
  • Drag and drop email builder
  • A/B testing and personalization features
  • High deliverability rates
  • Smart send functionality that allows you to adjust send times
  • Powerful analytics with data on opens, clicks, and time spent viewing email


  • Pricing on paid plans might be a factor for newer businesses


You can use HubSpot email marketing for free, which includes 2000 email sends/month. Paid plans start at $50/month.

6. 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.

This is a simple email service that can be a great choice for medium businesses who want their emails to go where they belong (your audience’s inbox).


  • 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


The free plan includes up to 10,000 emails/month (and up to 100 validations). You can choose Pay-As-You-Go pricing or sign up for a traditional plan. Pricing starts at $79/month.

7. SendGrid


SendGrid is a cloud-based SMTP email 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 website, 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


The free plan includes 40,000 for the first 30 days, 100 emails/day thereafter. Paid plans start at $14.95/month (number of emails: up to 50,000/month).

8. 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 site with a little help from WordPress 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


If you send emails using an application hosted in Amazon EC2 (U.S.): Free for the first 62,000 each month ($0.10 for every 1,000 over)

Sending email from an email client or other software (U.S.): $0.10 for every 1000 emails you send

Receiving emails (U.S.): Free emails up to the first 1,000 you receive, $0.10 for every 1,000 emails you receive after that.

Additional Charges: $0.12 for each GB of attachments

9. 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 mail client 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


Plans start at $10/month (number of emails: up to 10,000 emails/month).

10. 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


Plans start at $6/month per user.

11. Moosend


Moosend is an affordable SMTP email 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 and free SMTP service plans
  • Simple and easy to use A/B testing options
  • Great customer support
  • Advanced list of segmentation tools


The free plan includes up to 1,000 subscribers. Paid plans start at $10/month. Pay-As-You-Go plans start at $3 for up to 1,000 credits.

12. 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.

This is especially helpful for your unsubscribes, as you’ll want to keep an eye on those. Mailchimp charges by the number of contacts in your plan, and that includes subscribers who have been unsubscribed by not deleted.


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


  • Only works with Mailchimp


Pricing is based on blocks of 25,000 emails. For a single block of 25,000 emails, it’s $20.

13. Mailjet

mailjet homepage

Mailjet is a cloud-based transactional email service. It allows users to easily send marketing and automated emails, manage contacts, and so on.

The platform also features templates that can be used for mobile-friendly emails as well as plain text messages. They have both free and paid hosting plans with plenty of options for sending emails and other advanced features (like A/B testing).

It also comes with a free SMTP server that you can set up for transactional emails in a matter of minutes.

This helps you send more emails in less time while still protecting your deliverability rates.


  • Advanced email builder
  • Tons of pre-made email templates
  • Affordable
  • Variety of ports with an SMTP relay
  • Access to either TLS or SSL encryption


There is a free plan available to get started. Paid plans begin at only $15/month.

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 Email Service for Small to Midsize Websites:

Best SMTP Email Service for Larger Websites:

There you have it! We hope you found this article about SMTP services for reliable email marketing super informative. To push your email marketing to a higher level, check out these guides:

These articles are packed with info to help you better your email marketing strategy to optimize results and grow your business.

And if you’re looking to build your email subscriber list and generate leads, you may want to check out OptinMonster.

It’s the most powerful lead generation tool to grow your subscriber list. It makes it easy to create stunning popups, floating bars, scroll boxes, and other such campaigns that convert visitors into subscribers.

Want to start building your list right away? Get OptinMonster today.

Jacinda Santora
Jacinda Santora is a writer specializing in eCommerce and growth marketing. She prides herself on her ability to make complicated things easier. When she isn't writing you can find her daydreaming about campervans, drinking coffee, and listening to podcasts.


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