Our top 6 SMTP providers for transactional emails

Transactional emails are super important because they are a big part of your customer experience.  But, with almost as many options as a sushi menu (how are you supposed to choose?! 🍣), picking the best SMTP email service for your business can be overwhelming. What key features should a good SMTP service include? Will they all offer similar levels of deliverability?

To find out, I took a deep dive into the best SMTP service providers and emerged with 6 top solutions. Here’s my rundown of the pros and cons of each.

An SMTP service provides access to an SMTP server via an email client or web app so you can manage incoming and outgoing emails, kind of like a post office. 

It uses SMTP (Simple Mail Transfer Protocol) to relay messages from one email server to another (which is why it’s also know as an SMTP relay service). It’s the most reliable and secure way to send emails because it uses authentication techniques (SPF, DKIM, and DMARC) that allow them to be verified, making it more likely they’ll reach your recipients’ inboxes. 

Whenever you send an email, whether from a mail client like Gmail or an ESP (Email Service Provider) like MailerLite, the SMTP service is the system that actually sends your message across the internet. Larger organizations sometimes choose to set up and manage their own mail servers to handle email, but for the majority of businesses, using a third-party SMTP service is more convenient, cost-effective, and easy to manage.

Email marketing providers, like MailerLite, are optimized for the best deliverability of marketing campaigns, while transactional email services are optimized for sending high volumes of action or system-triggered emails from your website, app, e-commerce platform, or CRM.  

Additionally, to send marketing emails, you need opt-in consent from your subscribers. This isn’t the case for transactional messaging! Managing your newsletter subscribers and transactional recipients on the same platform can become messy, and could land your business in hot water if you mix them up.

When researching and testing, I looked at the most popular SMTP services on the market and narrowed down my selection based on what is generally considered the most important criteria for a high-performing transactional email service. This involved looking at the tool’s deliverability, interface and user-friendliness, customer support, and value for money. 

To assess each tool, I evaluated how quick and easy it was to sign up, create an email template, and send basic SMTP emails from platforms like WordPress. I also looked at how in-depth each tool’s API documentation is. Finally, I considered each SMTP service’s features, security, and documentation.

So, here are my top 6 SMTP service providers that I think are good choices for sending transactional emails. I’ve included what I liked about each, the pros and cons, pricing, and a look at each tool’s free plan or trial where applicable. 

But before we get to the breakdown of each tool, here’s a quick overview of the pricing and main features of each tools’ most basic paid plans.

Pricing

Main features

MailerSend is an advanced transactional messaging service built for developers to seamlessly integrate email sending into their app or website. Although it was designed for developers, MailerSend does offer a bunch of no-code options with plugins and automation platforms for more simple solutions. 

Plus, it has a really nice, intuitive interface that anybody can find their way around. Even non-technical users can easily design templates, create analytics reports, and manage invoices. 

One really simple but handy use case for SMTP services is that you can beef up the email delivery rates of WordPress emails, or other platforms that allow you to input your own SMTP credentials. I use MailerSend to send WordPress emails for a personal project. And OK, I admit, I may be a little biased since MailerSend comes from the creators of MailerLite, but I was blown away by how easy it was to set up and how well it works. Plus, I’ve played around with creating various automations using Zapier and loved how easy it was to build advanced workflows.  

If you’re a MailerLite user or just want a way to easily design professional email templates, you’ll be happy to hear that MailerSend also includes three email builders, including a drag and drop builder that’s almost identical to MailerLite’s.

Sign-up process: 10/10. Signup takes seconds and you’re able to test the tool instantly with a trial domain. There’s also a lot of documentation so adding your own domain is straightforward.

Create an email template: 9/10. MailerSend’s Drag & drop builder is very easy to use and includes more blocks and options than others I’ve tried. My only gripe (and it’s a small one) is that it can be a little finicky at times to select the right element and setting.

Create a basic SMTP setup: 10/10. MailerSend has it’s own WordPress plugin which is a big plus for WP users. It’s really easy to create a set of SMTP credentials and connect your account. All you need to do is input your SMTP username and password and create DNS records for your domain and that’s it. MailerSend starts handling your emails for you.

API documentation: 9/10. The documentation is in-depth, covers all of MailerSend’s features and includes code examples. 

Overall: 9.5/10

Key features: 

• Quick and easy SMTP integration

• Flexible and powerful API available with 7 regularly updated SDK libraries

• Rich-text, HTML and Drag & Drop email editors

• Inbound message processing to manage incoming emails and SMS

• Inbuilt email verification tool 

• Highly customizable custom user roles

• Transactional SMS

• Sign in via SSO and connect your MailerSend, MailerLite and MailerCheck accounts

• Dedicated IP addresses available for high-volume senders

Pros:

• 20% discount for yearly subscriptions

• Among the top performers for email deliverability

• Award-winning customer support

• Multichannel communication: Combine email and SMS

• Straightforward pricing plans

• Rich documentation including an API reference, developer guides, knowledge base articles and more

Cons:

• As of now, MailerSend isn’t fully integrated as a single solution with MailerLite

• Live chat support is only available for paid plans, however, the free Hobby plan has access to very responsive email support

Mailtrap is an email delivery service provider for businesses and individuals that covers testing, sending, and in-depth analytics on how emails perform. Mailtrap Email API/SMTP gives developers a stable working email infrastructure and control over their email deliverability. Unique monitoring capabilities provide effortless maintenance and troubleshooting. Mailtrap also has a good reputation for customer support and guidance to help users make the most of its features and solve technical issues. 

The interface is simple and straightforward, but I think that the navigation could be more intuitive. Mailtrap doesn’t have its own WordPress plugin so I tried to connect it with my site using the WP Mail SMTP plugin instead, which is easy to configure. Overall I think Mailtrap is a solid solution if you need very basic email sending and aren’t interested in other features. But it does have a sandbox testing feature for developers that sets it apart from other SMTP services.

Sign-up process: 8/10. After creating an account the first step is to provide additional information which can be a bit of a pain when you’re in the testing and research phase. 

Create an email template: 6/10. Mailtrap’s drag and drop template builder is easy to use but it lacks more advanced pre-built blocks that allow you to create really amazing emails.

Create a basic SMTP setup: 9/10. Works well with a third-party SMTP plugin and was simple enough to configure. 

API documentation: 8/10. Mailtrap’s API documentation is quite in-depth and covers most of its features. But its SDKs are not as comprehensive for some languages as for others. 

Overall: 7.75/10

Key features:

• Mailbox providers overview to view stats and deliverability for individual providers at a glance

• Built-in spam checker for emails

• Email Sandbox to test emails before production in a safe dev and QA environment

• Multiple inboxes for different projects and stages (Email Sandbox)

Pros:

• End-to-end sending solution that covers testing, sending, and tracking

• Responsive customer support and one of the few SMTP servers that offers 24/7 ticket support

• Mailtrap runs security checks in the background, so users only need to follow the in-app wizard to complete the domain setup

• SMTP and APIs compatible with Sendgrid, Mailgun, and Mandrill: Mailtrap supports standard SMTP protocol and has compatible APIs, which saves time and makes the switch to Mailtrap easier

• One of the cheapest solutions available

Cons: 

• Very limited integrations with other applications

• Limited options in the drag and drop editor 

• Lack of advanced features like inbound message processing and SMS 

Postmark is a popular SMTP service enjoyed for its user-friendliness, focus on deliverability, and decent customer support. It’s also one of the more pricey options available. 

It’s a solid choice for email sending, but I found the features to be a little bit basic. One thing I did like was the easy access to documentation throughout the app. With each feature, there are links to relevant docs and guides which make getting started much easier. 

Postmark also has very good testing features that allow you to test the API and see how various email activities will be handled. Plus its documentation is very comprehensive.

Sign-up process: 9/10. Signup takes seconds and there’s no need to provide additional information before getting to have a look around the tool. The only downside is that you can’t sign up with an email address that uses a free domain like Gmail, so you’ll need to use your business email. You can start testing straight away but you can only send to emails using the same domain that you signed up with. 

Create an email template: 3/10. Template creation is where Postmark loses marks. There is no user-friendly email builder available, only an HTML builder which won’t suit a lot of users. The tool does have a template library but the options are very basic and customizing them will involve editing the HTML code. Plus, the HTML editor doesn’t provide snippets either.

Create a basic SMTP setup: 10/10. Retrieving SMTP credentials is easy. Postmark also has its own WordPress plugin and instead of using SMTP credentials, you can enter an API key to connect to your Postmark account and start sending emails. It was super easy to set up and worked well. 

API documentation: 9/10. The API is very well documented but I wasn’t able to find code examples for different languages. I did like its API explorer which allows you to send API requests to your account. 

Overall: 7.75/10

Key features:

• Global SMTP service with endpoints maintained in regions around the world

• Email API available with several official SDKs

• Message streams feature for sending both transactional and broadcast messages

• Dedicated IP addresses available for high-volume senders

• Sandbox feature for testing

Pros:

• 45-day data retention period

• Consistently ranks high for deliverability

• Good customer support

Cons:

• One of the more expensive solutions

• No free tier available

• No user-friendly drag and drop template builders

Brevo (formerly Sendinblue) is an all-in-one digital marketing tool primarily targeted towards new and growing businesses, e-commerce sellers and agencies looking for a single solution to get started with. Email isn’t the only focus here. Brevo also includes CRM, marketing automation, sales tools, and more as well as email marketing and transactional email campaigns. 

The Brevo dashboard is nice and I find the navigation more intuitive than on some of the other platforms. It was super easy to find transactional email templates and start creating my own, and I really liked its drag and drop builder. It has a decent amount of blocks, especially for different text and image combinations, although it lacks more interactive and special content blocks like countdown timers or product blocks. 

The main issue I have with Brevo is that there are a lot of features in the app that, if you’re not using them, just get in the way. 

Sign-up process: 6/10. Initial signup is easy with Google SSO but before you get a look at the app, you need to provide additional information including your company name, website, address, how many people are on your team, and a mobile number (that you need to verify). 

Create an email template: 9/10. A nice and very user-friendly builder. It’s just missing some more advanced blocks that could be useful for transactional emails. 

Create a basic SMTP setup: 9/10. Getting started with a basic SMTP setup is generally easy but I couldn’t find where to add a domain at first, as this is located under Campaigns with no option under Transactional. But finding and configuring SMTP was straightforward and, again, Brevo has its own WordPress plugin that lets you enter your API key to start sending emails quickly and easily. 

API documentation: 8/10. Brevo has decent documentation but it doesn’t cover all of the API’s functions.  

Overall: 8/10

Key features:

• Brevo is a digital marketing platform providing several tools in addition to email

• Transactional email via API in several popular languages

• Includes an SMS feature for SMS marketing campaigns

• Dedicated IP available on the Enterprise plan

• A/B testing and segmentation

Pros:

• All-in-one solution: If you’re in need of one tool to do it all, Brevo is a good option

• The Conversations tool allow you to manage email, chat, Facebook, Instagram, and Whatsapp communication

• It’s an easy-to-use tool that allows for quick setup and integration

• A good drag and drop email builder

Cons:

• Email isn’t the main focus so Brevo’s expertise is spread out across many areas

• Additional tools are available and a extra cost, plus there are lots of add-ons for various features meaning that plans and pricing are not as straightforward

Mailgun is an email service provider geared towards developers and is heavily focused on their email API, so this is something to bear in mind. But they do offer SMTP integration. As it’s built for transactional email sending rather than email marketing, Mailgun’s sending infrastructure is optimized for deliverability and reliability.

The interface is intuitive and the dashboard includes stats and information that are useful. Plus, the navigation is user-friendly and well-categorized so it’s easy to find what you need to get started. Another bonus is that Mailgun includes a bunch of optimization and deliverability tools such as DMARC reporting, email health, and blocklist monitoring.

Sign-up process: 8/10. I almost gave the signup process a much lower score because initially, Mailgun asks for a payment method to be added at signup. But look carefully and you’ll see that you can opt out of this if you just want to check out the platform, so keep this in mind! Once you’re in, you’re greeted with a few main options which makes it easy to get started. 

Create an email template: 4/10. Mailgun has a visual template builder but it’s very basic, as are their templates. Plus, you can’t upload files such as images. To insert images into your templates, you need to add them via URL.

Create a basic SMTP setup: 10/10. It’s really easy to find and add your domains and then create SMTP credentials, plus there is a testing domain you can use to try it out. And, even better, Mailgun also has a WordPress plugin so it was super simple to test out on my WordPress website. I just needed to install the plugin and add the API key.  

API documentation: 10/10. Mailgun has great, comprehensive API documentation and I particularly enjoy how clean and organized everything is—it’s really easy to find what you’re looking for.

Overall: 8/10

Key features:

• Includes inbuilt deliverability tools

• Provides an advanced email API for various languages

• SMTP integration and documentation

• Send Time Optimization feature which holds email until recipients are viewing their inbox

• Dedicated IPs available as an add-on for high-volume senders

Pros:

• Committed to a 99.99% uptime SLA

• Well documented API 

• Extra tools for monitoring and optimizing deliverability that most platforms don’t include

Cons:

• Very basic visual email builder and HTML builder

• Many of the features and tools are quite technical, so may be difficult for beginners to get started with

Amazon Simple Email Service is a cheap, no-frills SMTP service for businesses on a budget. While it’s scalable and flexible, Amazon SES lacks the advanced inbuilt features, like tracking and email activity, needed to develop your transactional email strategy. So while Amazon SES may be one of the most cost-effective solutions for email sending, it’s not the most user-friendly, nor does it allow for effortless advanced configuration. 

The tool has a high learning curve that requires at least some familiarity of the AWS ecosystem. Also, plans with access to support costs extra with packages starting at $29 per month. Free support is only available for issues with your account or billing. 

Amazon SES provides a lot of decent features for programmatic email sending, which makes it more suited for developers. But you won’t find any email builders—if you want to create templates, you need to do it via the Amazon API. 

Sign-up process: 3/10. If you already have an AWS account, you can use that. If not, it’s a multi-step process to sign up that involves providing your name, address, phone number, and unfortunately, a payment method. Once you’ve signed up, you then need to find the email service.

Create an email template: 1/10. There are no builders available, you can only create templates via the API. 

Create a basic SMTP setup: 9/10. I did find it easy to locate the SMTP settings and create and manage SMTP credentials. This could make Amazon SES a really cost-effective solution if you send a high volume of emails through WordPress, WooCommerce or other similar platforms, and don’t need other advanced features. There isn’t a WordPress plug-in though, so a third-party plugin is needed.

API documentation: 8/10. Amazon’s documentation is quite comprehensive but not the easiest to read and navigate. 

Overall: 5.25/10

Key features:

• Offers three ways to send emails: SMTP, via the Amazon SES console and with the Amazon SES API (includes Amazon SES SDK)

• Virtual Deliverability Manager Mailbox simulator for testing

• Can be used for transactional emails, marketing emails and bulk email notifications

• Dedicated IPs available as an add-on for high-volume senders

Pros:

• Cost-effective and easily scalable: Amazon SES is the cheapest SMTP solution on this list with pay-as-you-pricing

Cons:

• Lacks additional features out of the box so a lot of crucial features, like tracking, need to be built from scratch

• Not a team-friendly solution and is aimed at developers

• Technical support costs extra

So now you’ve got a better idea about the platforms that are available, it’s time to think about the perfect recipe that makes the right SMTP service for your business. Let’s take a look at what should be on your radar.

Deliverability

When you’re sending important account information, password resets, order confirmations and more, it can be frustrating for customers when they don’t receive your emails. It can even lead to a loss of trust in your business. 

Here are two tips on how to find out if an SMTP service has strong deliverability:

• Check other users' reviews: Look for reviews on well-known and trusted third-party review sites, and search for those that specifically mention deliverability. 

• Check for proof points on their website: Do they talk about deliverability? What credentials do they have to back up their claims?

Price

Most SMTP services offer paid plans at different price levels with varying features. They’ll usually be priced based on the volume of emails. When choosing a service, as well as considering which one fits your budget and needs, think about how the service will grow with you in the future. Ask: 

• Does the service offer easy, affordable scalability?

• How easy is it to upgrade your plan should you need to? 

• And most importantly, is the service completely transparent about all of its pricing?

Customer support

Encountering problems and then learning that customer support is nowhere to be found is no fun. When researching an SMTP service’s customer support, think about:

• What customer support channels do they offer? Do they fit your needs?

• When is customer support available? Is it 24/7 or limited?

• What do current users say online in reviews and on social media? 

• Is customer support free or do you have to pay extra to access it?

Reputation control

Consider what features the service offers to help you monitor and manage sending  activity and deliverability rates so you can maintain a good sender reputation. An SMTP service should allow you to view bounces and spam complaints, add a webhook so you can get real-time notifications about such events, and provide a suppressions list or blocklist feature so that you can manage your email list. 

Documentation

Sometimes difficult tasks have a simple solution. Ample documentation can help you resolve issues quickly, saving you time and a conversation with support. A good SMTP service will provide comprehensive and easy-to-follow documentation to help you get started with their product as well as create more advanced configurations and integrations.

Ease of use

The easier the SMTP service is to use, the more productive your team will be when it comes to taking care of your transactional emails. Ask:

• Can you get started quickly and make use of advanced features easily? 

• How easy is it for people across various teams to contribute? 

• What features are available to make this possible?

Security

You’ll want to check that the service follows best practices and industry standards when it comes to protecting your and your customers’ data. Is the service clear about how they ensure that their service is secure? It might be tricky to find a lot of information about an SMTP service’s security, but look out for the following:

• How are they complying with international data protection laws such as the General Data Protection Regulation (GDPR)?

• Are their data centers compliant with the relevant security standards?

• Is data always processed over secure encrypted connections?

• Are they using the latest industry standard technologies?

Implementing SMTP is the best way to get started with secure, reliable and fast email delivery at scale. In this list of best SMTP services, we’ve included options for various budgets and needs, with everything from super simple, no-frills services, to more comprehensive transactional email services and whole marketing tools—there’s a solution for every business! Plus, with many of these services, you can get started with SMTP and graduate to an email API when you’re ready for more advanced features. 

Now you’re clued up on the best SMTP services, we want to know what you think! Tell us about your favorite SMTP services in the comments below.