11 Best SMTP services for transactional email

If you’re looking for a way to send transactional emails that get delivered, you’re going to need a dedicated SMTP service. 

With almost as many options as a sushi menu (how are you supposed to choose?! 🍣), picking the best SMTP service for your needs can be overwhelming. What key features should a good SMTP service include? Which are a must for your business? What are the pros and cons of each?

We’ll help you navigate the madness with a run-down of the 11 best SMTP services along with a guide to what to look for when scouting for the best SMTP services.

Simple Mail Transfer Protocol (SMTP) is an internet standard for sending and receiving emails on the internet. It’s a reliable way to relay messages as it uses email authentication, meaning that your emails can be verified and are more likely to make it to your recipients’ inboxes. 

An SMTP service provides access to an SMTP server via an email client or web app, so that you can manage incoming and outgoing emails. Gmail, Outlook and GoDaddy are examples of free SMTP services, however these have a limit on the volume of messages you can send. 

Fortunately, there are a number of dedicated SMTP services optimized for high-volume (over 2,000 emails per day) transactional sending, a few of which offer generous free plans to help you get started.

Whether it’s password reset requests, comment notifications, order confirmations or shipping updates, a dedicated SMTP service is the best way to ensure your emails reach the inbox. Built to securely and reliably transfer emails over the internet, and with a focus on deliverability, SMTP service providers do a lot behind the scenes to help you maintain a good sender reputation. 

What’s more, if you plan to send transactional emails at scale a simple web host or webmail provider will prevent this with strict sending limits. These popular providers often set limits on their SMTP servers from as little as 300 emails per day with further restrictions on the number of recipients. A third-party SMTP service takes care of this by providing generous sending quotas which allow you to optimize for high volume sending.

Both marketing and transactional email services are optimized for the best deliverability of their respective types of emails. Marketing ESPs work best for scheduled, opt-in marketing campaigns, while transactional messaging services are built to handle high volumes of emails triggered by users. 

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 should you mix them up.

So you’ve done your initial research—there are so many options! 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.

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: There is no better way to gauge how good a product is than reading reviews from real users. 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? Look for stats on delivery rates and statements about the service's commitment to deliverability. What credentials do they have to back up their claims?

Most SMTP services offer paid plans at different price levels with varying features. They’ll then 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: 

• Is the service easily and affordably scalable? 

• Are the features in the plan going to be suitable for you 6 months or a year down the line? 

• 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?

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? 

• How does the service react to users’ questions, issues and complaints on social media and in public forums? Are they responsive, helpful and compassionate?

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

Consider what features the service offers to help you monitor potentially harmful activity and manage it so you can maintain a good sender reputation. An SMTP service should allow you to view bounces and spam complaints, add a webhook to be notified of such events and provide a suppressions list or blocklist feature so that you can manage these recipients. This will allow you to only send to real, engaged recipients, preserving your sending quota and protecting your sender reputation and deliverability.

Sometimes seemingly difficult tasks have a simple solution. Ample documentation can help you to resolve issues quickly and with ease, 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.

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? For example, can your developers implement the service while your marketing and design teams take care of email content? 

• What features are available to make this possible?

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 it’s a good idea to 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?

• Do they have a dedicated security team?

• Are they using the latest industry standard technologies?

Phew! No one said finding an SMTP service would be easy, but now you know exactly what to look for. To make the research process as painless as possible, we’ve narrowed it down to the 10 best SMTP service providers and given a rundown of their key features, pros, cons and pricing.

Pricing

Main features

Email design

Deliverabiity

Performance tracking

Customer support

MailerSend is an advanced transactional messaging service built for developers to get a headstart on integrating their SMTP service, while offering a feature-rich, intuitive interface so that non-technical users can easily contribute. MailerSend comes from the creators of MailerLite and is built by deliverability experts with over 10 years of experience in the email industry. And, they provide award-winning customer support for a secure and reliable service that users can jump right into.

Key features: 

• Fast and reliable SMTP service optimized for deliverability and easy to scale

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

• Inbound routing to parse incoming messages to your application

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

• Inbuilt email verification tool to validate recipients’ email addresses before sending to them

• Extensive user management tools with custom roles and options for each team member

• Transactional SMS so you can reach more customers in the way that suits them best

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

• Dedicated IP address available for high-volume senders

• iOS app for monitoring and managing emails on the go

Pros:

• Discounts for yearly subscriptions: MailerSend offers considerable savings—up to 20%—if you sign up for a yearly subscription

• Experts in deliverability: Supported by a dedicated deliverability team with years of email expertise. Also includes IP pool management and a deliverability consultation

• Award-winning customer support: 24/7 email support for all users with live chat for Premium plans. MailerSend’s friendly support team has the technical knowledge to help out with all aspects of your account. Plus, onboarding assistance is available to help you get started

• Three types of template editors: If you opt to use the email API rather than the SMTP plugin, users of all ability—with coding knowledge or without—can create and edit templates with the rich-text, HTML and drag & drop editors

• SMS API: Send shipping updates, order confirmations, 2FA requests, emergency notifications and more with the transactional SMS API

• Straightforward plans and pricing: Plans include Free, Premium and Enterprise with pricing based on the volume of emails. All pricing is clear and transparent; MailerSend won’t surprise you with any hidden costs down the road

• Rich documentation: On top of the exhaustive developers documentation, MailerSend provides regularly updated documentation on their website covering everything from how to get started and verify a domain to how to create inbound routes and set up transactional SMS

Cons:

• Limited to one set of SMTP credentials per domain: You can add and verify as many domains as you like, however, each domain is assigned only one set of SMTP credentials

• Live chat support is only available for Premium and Enterprise: However, the Free tier has access to award-winning email support that is quick to respond

Mailtrap is an Email Delivery Platform 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 resolve any issues that may arise. 

Key features:

• Email API has two sending options: Email API and SMTP Service

• Actionable in-depth analytics with a helicopter view dashboard to check all the significant numbers at a glance

• Up to 60 days of detailed logs to check email extended history

• Deliverability alerts to catch and fix unexpected sending issues before anybody complains

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

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

Pros:

• End-to-end sending solution: Mailtrap offers a wide range of tools and features to help users manage and deliver their emails effectively, including testing, sending, and tracking

• 15+ years of experience building email infrastructure: Mailtrap has been in the industry for more than 15 years, gaining a wealth of experience in building and managing email infrastructure for successful businesses

• Highly responsive customer support: The Mailtrap team is committed to delivering exceptional service through guidance and support to help users get the most out of the platform

• Secure and user-friendly setup and onboarding: 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

Cons: 

• Limited integrations: Mailtrap has fewer integrations with other email marketing tools than some other major platforms (e.g., Mailgun or Sendgrid)

• No 24/7 support and no live chat: you can contact Mailtrap support only via email

• No options for easy template editing: Mailtrap doesn’t include any drag and drop or rich-text template editors, however an HTML editor is in development. 

Coresender is more developer focused, providing APIs in addition to SMTP integration, but lacking flexible user roles and email editing tools for non-technical users. It is, however, uncomplicated for developers to implement and provides a reliable service with good deliverability. 

Key features:

• Simple SMTP integration with numerous apps

• Email API available with 4 SDK libraries

• Ability to create separate sending accounts, for example, for transactional and marketing emails or for different marketing initiatives

• Dedicated IP available available for Gold plan and above

Pros:

• Prioritizes transactional email: Although Coresender allows users to send both marketing and transactional emails, they ask users to select which types of emails they’ll be sending during account set up so that transactional delivery can be prioritized

• Good reputation for customer support: Coresender only offers email support at this time but they have a good track record for being responsive and providing friendly and helpful assistance to users

• Easy to get started: Onboarding and implementation is simple

• Solid email delivery: Uses clean IPs and providers a reliable rate and speed of delivery

Cons:

• No options for easy template editing: Even if you opt for the API instead of SMTP, Coresender doesn’t offer any tools, such as drag & drop or rich-text email editors, to edit email templates

• No free tier available: Coresender offers a free trial of 100 emails per month but no free tier for small volume senders

• No inbound email support: There are fewer advanced features including inbound routing, meaning there is no way to integrate incoming messages into your app

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, but it does include a rich feature set as well as documentation and webinars.

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

• Rebound feature which notifies users if their email address needs updating

• Dedicated IP address available for high volume senders

Pros:

• Long data retention period: Postmark offers the longest data retention period in this list of best SMTP services at 45 days

• Proven track record for deliverability: Postmark customers mostly note that they have received good deliverability with the service. Postmark also shares deliverability stats on their website

• Good customer support: Their customer support team is known for being quick and knowledgeable and is one of the top benefits among users

Cons:

• Not competitively priced: One of the main cons among Postmark users is the high cost of the service, which places it among the priciest on this list

• No free tier: Postmark doesn’t offer a free low volume plan and only provides a limited volume free trial

• Not the most user-friendly: Many features and functionalities are reported as not being user-friendly or intuitive; it’s a common theme that it takes some practice to get the hang of some elements of the app

Sendinblue is an all-in-one digital marketing tool primarily targeted towards new and growing businesses, ecommerce sellers and agencies looking for a single solution to get started with. Email isn’t the main focus here. Instead Sendinblue also includes CRM, marketing automation, Facebook ads, chat and more as well as email marketing and transactional email campaigns. 

Key features:

• Sendinblue 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, Sendinblue is a good option

• User-friendly: An easy-to-use tool that allows for quick setup and integration. Onboarding is often praised by users

• International presence: Sendinblue has a reach across the globe with headquarters in the US, Canada, Europe and India, supporting over 300,000 users in 160 countries

Cons:

• Email isn’t the main focus: Sendinblue’s expertise is spread out across many areas—it is mostly a CRM and marketing automation solution.

• SMTP isn’t a core feature: They provide transactional email via API and if you need SMTP, you need to reach out to Sendinblue to have it activated

• Limited support channels: Email support is available with priority support for Enterprise customers, but there is no live chat support

Mailgun is an email service provider geared towards developers and heavily focused on their email API but they do offer SMTP integration. As it’s built for transactional email sending rather than email marketing, Mailgun’s sending infrastructure is seemingly optimized for deliverability and reliability.

Key features:

• Includes inbuilt deliverability tools such as email verification

• Provides an advanced email API for numerous languages

• SMTP integration and documentation

• Provides live chat support

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

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

Pros:

• Committed to reliability: On their website, Mailgun commits to a 99.99% uptime SLA

• Easy to get started with API: With Mailgun’s developer focused approach and APIs, it’s easy to integrate into your website or app. 

• Trusted solution: Mailgun is used by over 100,000 companies and some well-known brands

Cons:

• Mixed opinions about deliverability: Despite being heavily focused on transactional email and deliverability, Mailgun reviews are a mixed bag with some users experiencing issues

• No email builders: Only an HTML builder is available for creating templates

• Love it or hate it customer support: Some Mailgun user reviews report positive experiences with customer support, while others report that support response times are slow and replies are canned responses. What’s more, several users have reported having their accounts suspended without notification

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

Key features:

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

• Reputation and Deliverability dashboards so that users can monitor events that may affect their deliverability rates

• Mailbox simulator for testing how applications will handle specific email delivery scenarios

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

• Dedicated IP 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 which also makes it easy and cost-effective to scale

• Extremely generous free tier if sending email from an app hosted on Amazon EC2: The first 62,000 emails per month are free

Cons:

• A hassle to add advanced features: As Amazon SES is a scaled back and simple SMTP solution, it lacks additional features out of the box that other SMTP services include. This means more advanced configurations must be built manually

• Lack of documentation: Documentation can be difficult to follow and is somewhat unorganized

• Not a team-friendly solution: Amazon SES is built for developers and lacks the features needed to allow the whole team to contribute to your email strategy

• No support included: To gain access to support, you must purchase and additional Amazon support package which can be costly for small businesses

SparkPost is a popular email platform among large enterprises and senders of large numbers of emails, due to its focus on deliverability, scalability, and regulation and compliance. It’s for this reason that their target customers include those in Financial services and FinTech.

Key features:

• SparkPost Signals feature provides insights using analytics and industry trends to predict potential email issues before they impact business

• Email verification tool

• Inbox tracker deliverability analytics tool

• Email API available with libraries for several languages

• Competitive email intelligence tool

• Dedicated IP address available for Premier plans and above

Pros:

• Rich feature set: Full-featured and user-friendly with a focus on analytics and data tools

• Good deliverability: Users of SparkPost report good deliverability 

• Easy to get started: With its email API and simple SMTP integration, SparkPost is easy to set up 

• Ample documentation: Rich and up to date documentation is available for help getting started, advanced features and troubleshooting

Cons:

• Limited customer support channels: Support is available via email but there is no live chat support

• Limited email editing options: SparkPost has a good HTML template editor but there is no rich-text or drag and drop available

• No templates: There is also no template library available for users

• Mixed reviews about support: A number of user reviews have reported that accounts have been suspended with no notification or explanation, as well as issues reaching support

• Issues with reliability: Many of these reviews are in relation to product updates which have affected the service status of accounts

Mailchimp is a popular email marketing service that offers SMTP transactional email as a paid add-on (previously known as Mandrill). In addition to email marketing, Mailchimp has expanded to offer a range of digital marketing tools including CRM, websites, ads and social media.

Key features:

• Comprehensive marketing platform for transactional email, email marketing and more

• Send emails via SMTP or API

• ROI (Return On Investment) tracking 

• A/B testing support

• Dedicated IP available for high-volume senders

Pros:

• Large number of integrations: Mailchimp has over 300 integrations on its website

• Seamless experience for existing Mailchimp users: If you’re already using Mailchimp’s other marketing tools and email, the transactional email add-on makes it easy to get started

• Simple well-documented API: Easy to get started with the documentation and official libraries available

Cons:

• Not available as a standalone product: To use Mailchimp Transactional Email, you must first be using the main Mailchimp App and then purchase the transactional email add-on

• Expensive solution: Mailchimp is among the most expensive SMTP services and offers no free tier

• SMTP service is not the core focus: The Transactional Email add-on is just that—it’s not a main feature of the solution, which has now become more focused on digital marketing tools and marketing automation

• Limited templates: Users have reported that there is a lack of good free templates and the capability to sufficiently edit them

SendGrid is one of the most recognizable and largest email delivery services available, and is a transactional and email marketing tool built for both developers and marketers. Supported by communications company Twilio, SendGrid is also able to extend its offering via additional Twilio features such as a transactional SMS API, video and WhatsApp. 

Key features: 

• Email API available in several popular languages

• Access to Twilio products and APIs

• Personalized support, deliverability consultation and onboarding available at an additional cost

• Email validation to clean your email list

• Dedicated IP address available for high-volume senders

Pros:

• Trusted solution: SendGrid has a portfolio of large companies and brands as users of the platform

• Built for teams: Enables developers to easily implement transactional email while marketing teams can collaborate to non-technical tasks

• Rich customer communication solution: With the technologies of Twilio, SendGrid is more than email. Businesses can communicate with customers through a variety of channels

Cons:

• Unreliable support: There has been negative feedback from users about the level of support they have received

• Inconsistent delivery: Users have reported being faced with IP blocks on shared IPs, leading to mixed results when it comes to email delivery

• User interface could be more intuitive: SendGrid reviewers have commented that they have found the interface to be confusing and lacking in usability

• Price: Compared to other solutions, SendGrid is a more expensive option before considering any add-ons

Mailjet has been around since 2010 but is now under the ownership of Sinch (Mailgun). It aims to offer a simple emailing solution that has a powerful impact for businesses’ customer communications. They have a strong focus on collaboration, aiming to simplify email sending so that businesses can spend more time focusing on growth. 

Key features:

• Secure SMTP integration as well as email API available

• Deliverability consultation available for custom plans

• Drag and drop and rich-text email editors with real-time collaboration

• Email automation feature to create automated workflows

• SMS API available

• Dedicated IP address for plans 100k+

Pros:

• Global presence: Customers in over 150 countries around the world

• Partnered with Mailgun: Mailjet users now have access to features available from Mailgun

Cons:

• Slow customer support response times: Users have commented that they have had to wait days for replies and that oftentimes responses are not satisfactory and support is not helpful

• Pricing has increased: Mailjet’s pricing has gone up since being acquired by Sinch, placing it among the most expensive SMTP services available

• Unreliable app: Although Mailjet guarantees a 99.9% uptime SLA, many users have reported issues with their servers, complaining that the app is slow and often doesn’t work

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.