SMTP Providers Compared: Choose the Best One for Sending Transactional and Marketing Emails

On January 01, 2024
10min read
Denys Velykozhon Marketing Lead @Railsware

Picture this: You’ve crafted the perfect email, the content is spot-on, and you’re ready to hit Send… But wait; are you sure your emails are going to reach their destination? 

The answer largely depends on the SMTP providers. These unsung heroes of email delivery work behind the scenes to ensure your messages reach their intended recipients promptly and reliably. 

In this article, we’ll leap into the realm of the given providers, unveiling the top three players in the industry. 

From need-to-have features to cost-effective solutions, we’ll explore the ins and outs of each provider, helping you make an informed choice

But before we start with the nitty-gritty, let’s have a quick overview of the contenders. 

Best SMTP providers: a quick summary

Provider TypeFree Email LinitPricing 
MailtrapEmail Delivery Platform Testing – 100 emails/month
Sending – 1000 emails/month
Testing – $14.99
Sending – $10.00
SendGrid Email Service Provider100 emails a day Essentials – $19.95
Pro – $89.95
Amazon SESEmail Sending Service62K emails for EC2 and Elastic Beanstalk usersPay-as-you-go – $0.10 for every 1,000 emails 

Mailtrap Email Delivery Platform

Mailtrap Email Delivery Platform, offers both Email Testing and Email Sending solutions. It provides a secure environment for testing emails, analyzing and fixing errors, and ensuring deliverability. 

There’s a variety of features like helicopter-view dashboards, deliverability alerts, email logs, and more. Although it has a free tier that allows up to 1,000 emails per month, high-volume businesses might need to opt for the paid plans.

Twilio’s SendGrid

As one of the largest SMTP providers, SendGrid offers diverse sending options and supports a wide range of email infrastructures. However, it may not be ideal for marketers requiring advanced segmentation and automation features. 

SendGrid also offers varying levels of customer support depending on the plan. While it has a free plan, access to more advanced features and capabilities requires premium subscriptions. For more info on SendGrid, jump here.

Amazon SES

Amazon’s Simple Email Service (SES) is a cloud-based, cost-effective service designed for businesses of all sizes. SES’s strength lies in its scalability, but integrating it can be labor-intensive and time-consuming because it requires technical expertise. 

SES lacks detailed reporting on email metrics and doesn’t provide a testing environment like Mailtrap. But there are generous free plans if your only focus is on the price.

So far so good, however, the devil is in the details. So, the following sections dive deep into the technical criteria you should know to make an educated choice. For more info on SES, jump here.

Criteria to consider when choosing an SMTP provider

A reliable SMTP (Simple Mail Transfer Protocol) provider is more than just the one with an appealing interface or a catchy name. 

Choose well, and you’ll get a balance of deliverability, reputation, pricing, and customer support; all aimed at helping your emails reach the recipients without a hitch. 

Now, we’ll help you figure out how to evaluate the best SMTP service providers and select the one that ticks all the right boxes. 


Remember that perfect email from the intro? It’d be frustrating to realize that the email keeps landing in the recipient’s spam folder. Though, your frustration can be easily avoided. 

If your SMTP service provider has a strong focus on email deliverability, there’s little to worry about. On that note, an ideal provider should offer:

Additionally, providers like Google’s free SMTP service and Mailrap Email Sending Free Plan are available for individuals and organizations looking for a zero-investment solution to send emails. Yet, you get all features mentioned above to help with deliverability. 

But analyze your emailing requirements closely before choosing a free SMTP server as there are other limitations – number of emails, email logs retention, user management, etc. 


As your email needs grow, you’d want an SMTP provider that can scale with your business. 

Consider the volume of emails you anticipate sending and whether the provider offers flexible plans or pricing tiers to accommodate your growth. Scalability is crucial to avoid hitting sending limits or facing sudden cost increases. 

For example, Mailtrap Email Sending Individual 10K plan starts at 10K emails a month for $10. But you can scale up to 100K emails a month on the same plan without paying 10x the price


Whichever way you look at it, the reliability of an SMTP email delivery service is paramount

You need an SMTP provider that guarantees high uptime and minimal service interruptions. Downtime can lead to missed opportunities, frustrated customers, and a negative impact on your business. 

Look for providers with a track record of reliability, redundant infrastructure, and robust disaster recovery mechanisms

Sounds cool, but what does this actually mean, and how to look for it?

In the context of SMTP providers, redundant infrastructure would involve having multiple servers, network connections, and storage systems to prevent single points of failure and minimize downtime. 

Knowing that, it’s worth considering a provider that offers the following:

  • Multiple data centers or server locations
  • Load balancing and failover mechanisms
  • Network redundancy (redundant network connections from different providers)

Tip: Mailtrap offers ActionMailer balancer you can use to further strengthen your email infrastructure if one SMTP email service fails. Check it out at GitHub

As for the robust disaster recovery mechanisms, these involve having comprehensive plans and processes in place to recover from major disruptions, such as natural disasters, system failures, or cyber-attacks. 

These mechanisms ensure that the SMTP provider can quickly restore operations and maintain service availability to minimize downtime and data loss

Here are some examples of best practices, though a lot of providers won’t be super-explicit about the exact methodology applied due to safety reasons. 

  • Regular data backups

The provider should perform regular backups of email data to prevent data loss in case of a disaster or system failure.

  • Replication and synchronization 

Critical data, such as user accounts and email configurations, should be replicated and synchronized across multiple servers or data centers to ensure redundancy.

  • Failover and failback procedures 

The provider should have documented processes for transitioning operations to backup systems during a disaster and for reverting back to the primary systems once the situation is resolved.

  • Testing and validation

Disaster recovery plans should be regularly tested and validated to ensure their effectiveness and identify any potential gaps or weaknesses.

Features and Integration 

Depending on your specific needs, you may require features like:

Think about the functionalities that are essential for your email campaigns and choose a provider that offers a comprehensive suite of tools to enhance your email marketing efforts.

Support and Customer Service

Let’s face it, even the best technology can encounter glitches or require assistance. That’s why reliable customer support is crucial when selecting an SMTP provider. 

Look for providers that offer responsive support channels, such as live chat, email, or phone support. 

Prompt and helpful assistance can save you time and frustration, ensuring that any issues or questions are addressed swiftly. Remember, good customer service can make all the difference when you need a helping hand.

We’ve armed with all the critical criteria, so it’s time to choose the best provider. 

SMTP provider #1. Mailtrap Email Delivery Platform

Mailtrap is an Email Delivery Platform that allows you to Test, Send, and Control your email infrastructure – all in one place. 

It’s ideal for both businesses and individuals looking for a reliable SMTP provider with a specific focus on deliverability. So, to no surprise, some of Mailtrap’s clients include StackOverflow, PayPal, Atlassian, and Adobe.

Note that Mailtrap offers both Email Tesing and Email Sending. The testing solution is a fully integrated sandbox allowing users to capture SMTP traffic in non-production environments. 

With that, you prevent unwanted emails from reaching users during the testing phase. Plus, you can analyze and fix HTML/CSS errors in your emails, ensuring they look and work as expected without spamming your audience.

On the other hand, Mailtrap Email Sending is a reliable transactional email service. It provides high-deliverability email infrastructure and effortless maintenance. The key features include:

  • Helicopter-view dashboards
  • Deliverability alerts
  • Email logs 
  • Deliverability stats for all Mailbox Providers (Office 365, Outlook, Gmail, Google Workspace, and more)
  • Email categories
  • Webhooks 
  • Email templates

Also, Mailtrap is soon to release Bulk Emails – an email marketing service you can use within the same Email Sending plan as transactional emails. 

Fill out this form and take one of the first few hundred seats

The benefits 

  • Testing and Validation

As mentioned, you can use Mailtrap to test and validate your emails in a staging environment before sending them to actual recipients. This helps to prevent any errors or issues from affecting your users.

  • Error Analysis

Mailtrap allows you to capture SMTP traffic and analyze your email for any HTML/CSS errors. This ensures that your emails look and work as they should when they reach your users.

  • Integration 

You can easily integrate Mailtrap with your application and start sending emails to your recipients’ inboxes. You just need to copy-paste SMTP credentials and verify a domain to get started. Or use our API and SDK libs.

Important Note: Testing, Sending, and Bulk [Coming Soon] Email APIs are different. 

  • Scalable and secure cloud-based infrastructure

We took the best practices for building email infrastructure and infused them with the latest and greatest in security, load balancing, and system redundancy. Then, we brought everything to the cloud for your convenience. 

But don’t take our word for it. Test it out yourself and feel free to tell us how it feels. 

  • Monitoring 

Mailtrap offers unique monitoring capabilities to control your email infrastructure performance and troubleshoot unexpected sending issues easily and fast. 

Pros & cons 


  • Mailtrap effectively captures outgoing mail in non-production environments, preventing unwanted emails from reaching users during testing.
  • It offers comprehensive error analysis and troubleshooting features, allowing you to fix any issues before your emails reach your users.
  • There are clear setup instructions for many different project types, making it easy to integrate both Mailtrap Sending and Testing into your application.
  • Mailtrap provides a secure and reliable infrastructure for production emails. Plus, there’s a team of people to ensure our systems and IPs are spammer-free without making you fill out lengthy verification forms. 


  • Mailtrap’s free tier has a limit of 1,000 emails per month, which may not be sufficient for businesses with high email volumes.


As mentioned, Mailtrap offers a free tier that allows users to send up to 1,000 emails per month. This free plan is quite generous, especially since it includes webhooks, email analytics, suppression management, and more. 

For businesses with higher email volumes, Mailtrap offers several paid plans with higher email limits, starting at 10K emails a month for $10.

SMTP provider #2 – Twilio SendGrid 

As one of the oldest and biggest SMTP providers, Twilio’s SendGrid needs little introduction. It’s an email service provider with a strong focus on the diversity of sending options with a host of different features to support email infrastructure. 

But why does SendGrid take second place? 

Twilio’s SMTP relay service and API, may not be the best fit for marketers looking for a comprehensive email marketing solution. More demanding users may find it’s in need of an update in areas such as advanced segmentation and automation. 

Also, SendGrid has different support levels depending on your plan. On the other hand, Mailtrap provides equal support for all its users. 

The benefits 

  • Email Deliverability

SendGrid’s primary focus is on ensuring your emails reach the recipients’ inbox and not their spam folders, which is a significant advantage for users focusing on this aspect. 

But take this with a grain of salt.

Depending on your plan, and the shared IP assigned to you, the delivery rates might not be as high as you expect. Ideally, you should opt for a dedicated IP with SendGrid. 

  • Analytics 

SendGrid offers detailed reporting functionality that allows you to track emails by category and campaign. 

Now, the level of detail with SendGrid’s analytics is a blessing and a curse. 

Data tables may appear overwhelming and, at the same time, you might need to keep clicking through menus to find a specific data point. 

  • Email Editor 

SendGrid provides a sophisticated email editor that allows you to add tags to your emails with common customer information, such as name and location. That helps personalize each campaign individually. 

And, if we’re perfectly honest, SendGrid’s drag and drop editor could be more convenient than Mailtrap’s Email Templates. Ours is mostly geared towards developers, whereas SendGrid’s could be easier to navigate for non-tech teams. 

Pros & cons


  • SendGrid provides a useful dashboard and automatic tracking for clicks, links, and Google Analytics integration.
  • It offers a separate API service that uses webhooks to ensure seamless data flow between different solutions.


  • SendGrid’s design can be confusing. Simply put, there’s a bit of a learning curve, and in time, you get the hang of it. 
  • As mentioned, SendGrid lacks robust segmentation and automation features, which can limit its usefulness for marketers looking to create highly tailored complex campaigns.
  • Lastly, if you’re on one of the lower plans, chances are you’ll be waiting for customer service quite a bit.


SendGrid does offer a free plan, but it is notably limited compared to Mailtrap’s offering. For additional features and capabilities, SendGrid offers several paid plans. However, the full functionality of email automation is only available to premium users. The specific pricing details for these plans can be found on SendGrid’s website.

SMTP provider #3 – Amazon SES

Amazon Simple Email Service (SES) is a cloud-based email-sending service designed to send emails quickly and securely. It’s a reliable, cost-effective SMTP provider for businesses of all sizes, particularly if they’re on a budget.

However, integrating SES is labor-intensive and can be time-consuming. Typically, you need a dev experienced in email infrastructure, AWS integrations in particular. So, make sure to factor that in when considering Amazon as an option. 

Nevertheless, with pay-as-you-go pricing based on the number of emails sent, it allows you to scale email sending without breaking the bank. That makes Amazon SES a strong contender, assuming you have the experience or human resources to integrate it. 

The benefits

  • Scalability

Amazon SES can handle a high volume of emails, making it suitable for organizations with large email lists or that need to send a large number of emails on a regular basis.

  • Deliverability 

Amazon SES uses machine learning and other techniques to help improve the deliverability of emails, increasing the likelihood that emails will be delivered to their intended recipients. 

  • Integration 

Amazon SES can be easily integrated with other AWS services and third-party applications, allowing organizations to build custom email solutions or integrate email communication into their existing systems.

But remember, these are heavily technical integrations where you might need help from an experienced developer.

Pros & cons


  • Low cost, especially for high email volumes.
  • High deliverability and scalability.


  • Complex setup and configuration, particularly for those who are not experienced with AWS.
  • It lacks detailed reporting on email opens, clicks, bounces, and other metrics.
  • Unlike Mailtrap, it does not provide a testing environment to catch errors before emails reach users.

Note: It’s possible to use a third-party integration to get more deliverability data from SES. Then again, it means more programming and additional cost. 


Amazon SES offers both a free tier and paid plans, with pricing varying based on the number of emails sent. The free tier allows you to send up to 62,000 emails per month when sending from an Amazon EC2 instance or AWS Lambda function.

Paid plans start at $0.10 per 1,000 emails sent. 

Summing up

In the realm of SMTP providers, Mailtrap, SendGrid, and Amazon SES stand out with their distinct offerings. Mailtrap’s focus on the platform approach (Test, Send, and Control) makes it an ideal choice for developers. Plus, it provides generous free email limits for both Testing and Sending. 

SendGrid handles transactional emails well and offers a free email limit of 100 emails/day. 

Meanwhile, Amazon SES caters to high-volume transactional email needs, allowing up to 62,000 free emails per month on a pay-as-you-go pricing model. But you might not be able to integrate it on your own. 

Whichever provider you prefer, make sure to choose the one that gives you the most optimal balance of key features, price, and deliverability. 

Provider TypeFree Email LimitPricing 
MailtrapEmail Delivery Platform Testing – 100 emails/month
Sending 1000 emails/month
Testing – $14.99
Sending – $10.00
SendGrid Email Service Provider100 emails a day Essentials – $19.95
Pro – $89.95
Amazon SESEmail Sending Service62K emails for EC2 and Elastic Beanstalk usersPay-as-you-go – $0.10 for every 1,000 emails 


Article by Denys Velykozhon Marketing Lead @Railsware

With a decade of experience in content marketing, I specialize in launching custom email campaigns that drive engagement and conversions. Let’s explore the art and science of creating personalized content that resonates with your audience and delivers outstanding results. Join me on this blog to master the art of impactful email campaigns.