Transactional emails are an untapped opportunity—they're often one of the first emails a customer or subscriber receives from you, and they have incredibly high open rates. Way higher than marketing emails.
An order confirmation, a welcome email, a dispatch update, and even a new device login—they're all opportunities to build and strengthen customer relationships.
I've been researching, testing, and writing about email marketing software for the last four years. And I know the decision to choose an email tool can be time-consuming. To update this list for 2023, I spent several weeks researching and testing over two dozen transactional email apps. Based on that experience, here are the five best.
The best transactional email services
SendGrid for transactional emails and email marketing in one
Mailchimp Transactional Email for Mailchimp users
Postmark for quick email delivery
MailerSend for a drag-and-drop email builder
SparkPost for thorough email analytics
What makes a great transactional email service?
How we evaluate and test apps
All of our best apps roundups are written by humans who've spent much of their careers using, testing, and writing about software. We spend dozens of hours researching and testing apps, using each app as it's intended to be used and evaluating it against the criteria we set for the category. We're never paid for placement in our articles from any app or for links to any site—we value the trust readers put in us to offer authentic evaluations of the categories and apps we review. For more details on our process, read the full rundown of how we select apps to feature on the Zapier blog.
Picking a tool to send transactional emails is tricky—there are tons of options offering similar services and competitive pricing. I started by figuring out what the essential features were for apps in this category. Here's what I looked for during my evaluation of transactional email providers:
Value for money. Transactional email tools are a heavy investment. It's essential to get a feel of the app before purchasing, so the best transactional email apps aren't just competitively priced but also include a free trial to test out the features without a financial commitment.
Ease of setting up. There's nothing more frustrating than signing up for a transactional email app, making an account, and then being unable to figure out how to configure your domain. Your team—developers or not—should be able to easily log in to the app and set it up for action.
Customer support. Even the experts need help sometimes. Success with a transactional email app means getting quick and reliable support—whether that's in the form of live chat, email, or phone. The best tools also have an extensive and updated knowledge base so you can help yourself when possible.
Analytics. While the need for data differs from business to business, comprehensive numbers hurt no one. The best transactional email apps check the basic boxes of analyzing your open rate, bounce rate, and spam complaints—and also go beyond that, to share delivery insights that can improve your emails.
Deliverability. There's nothing worse than a customer receiving their dispatch status email in spam, or worse, not receiving any update at all. The ideal transactional email app has excellent deliverability—ensuring you land in your customers' inboxes on time.
To find the best options, I signed up for free trials of all the apps that met my criteria and tested them. I added contacts, drafted an email, and sent two or three test emails for each app—unless their domain verification process made it impossible to move ahead with testing. Along the way, I took notes on everything I encountered—what I liked and what I didn't like.
I also read user reviews to better understand how the various features held up over a period of several months or years, versus just a few weeks. For example, I checked to see if there was overwhelmingly negative feedback about deliverability or bounced emails when the volume of emails increases as a business scales. Once I'd narrowed down the list, I tested the shortlist again, even more in-depth, to be sure each service lived up to its unique selling point. And that's how I landed on these five apps.
Best transactional email service for transactional emails and email marketing in one
If you want to manage your transactional emails and marketing emails under one roof, SendGrid is the way to go. Transactional emails are at the core of SendGrid's business, so it's no surprise it's a killer in this domain. And it stacks up really nicely against some other big names.
For example: SendGrid outshines Mailchimp with its intuitive email editor as well as its deliverability insights. SendGrid offers an expert insights report, deliverability metrics, category comparisons, and more. And because SendGrid is a transactional email app first and foremost, it has all the features—whereas the standard Mailchimp UI and data aren't present in Mailchimp Transactional Email. Similarly, SendGrid outshines other apps like Sendinblue with its API integrations and support for multiple frameworks like Java, PHP, Go, Python, and C#.
SendGrid's email templates are great for customizing and branding emails. There are a lot of options to add your brand logo, alter the design, and even add your own code. I was also impressed by their email testing—you can do inbox rendering and test your emails for how they look and deliver on different devices. But this ease of use comes with a trade-off: SendGrid probably wouldn't be your ideal choice of email marketing app if you're looking for complex automation and workflows.
The email testing capabilities, combined with SendGrid's comprehensive analytics, make it super easy to continually improve your emails based on feedback. So if you want to do your email marketing and transactional emails in one place—without sacrificing the quality of the transactional side of things—SendGrid is my pick. (You can also purchase marketing and transactional email services separately if you don't want to commit to both services off the bat.)
You can automate SendGrid with SendGrid's Zapier integrations to do things like automatically sending transactional emails based on new form submissions or spreadsheet updates.
Send emails through SendGrid for new Typeform entries
Send emails to new Facebook Lead Ads leads via SendGrid
SendGrid pricing: Free for up to 100 emails/day. The Essential plan begins at $19.95/month and includes 50,000 emails, guaranteed response time on ticket and chat support, and more.
Campaign Monitor and Mailmodo are good alternatives to SendGrid, but they didn't meet my criteria for a free trial or affordable pricing for the transactional email service.
Best transactional email service for Mailchimp users
The email marketing leader Mailchimp designed Mailchimp Transactional Email (formerly Mandrill) as a paid add-on, so any Mailchimp user has a viable option for sending transactional emails straight from Mailchimp. So if you're using Mailchimp as your email marketing tool, there's no reason to use a different app for transactional emails. (I wouldn't recommend it if you aren't already using Mailchimp because you have to create a Mailchimp account to use Mailchimp Transactional Email—you can't purchase just the latter like with SendGrid.)
Mailchimp has robust API documentation—which was helpful for me as I navigated the system—and you can start sending via transactional API or an SMTP integration. And there's a lot of room for setting up rules and optimizing customer journeys. For example, you can set up a "Reminder" email sequence at regular intervals for any email subject line that includes the word "event" (to nudge your subscribers to join an event they've signed up for).
There's nothing groundbreaking in the analytics department—just the basics of top email clients, top operating systems, and URL tracking. But, while I wasn't able to test this feature, you can create your own comparison reports to group different emails and analyze data (compare data between different sender IDs, different API keys, different templates, or your own tags). This feature would come in handy if you wanted to create customized reports—for stakeholders or for your team's use.
The main problem I had was that, in order to send an email, you need to configure DKIM and SPF settings, which require you to update the TXT records with your domain host at the backend. It's a few extra steps, and it's complicated if you already have an SPF record added to your domain and need to add a second one for Mailchimp. That's the situation we were in, so I couldn't actually send a test email—but if you already trust Mailchimp to send your emails, you'll be able to rely on Mailchimp Transactional Email too.
Mailchimp also has a unique pricing structure: instead of the classic monthly plans, you can purchase "blocks" based on the number of emails you need. For example, if you need 10,000 emails for one month, you'll purchase one block at $20. This option is great to have if you have seasonality in your business and won't need the same number of emails each month.
But remember: a con of this unique pricing method is the purchased blocks don't transfer to the next month if left unused. So if you purchased a block for 10,000 emails but ended up using only 8,000, the remaining 2,000 emails would be wasted because you couldn't carry them to the upcoming month.
You can automate Mailchimp Transactional Email with Zapier, connecting it to all the other apps in your stack. That way, you can do things like automatically receive Slack notifications for every new bounced transactional email or send template Mailchimp emails when new Mailchimp Transactional subscribers are added.
Get Slack notifications for new bounced Mailchimp Transactional emails
Send template Mailchimp emails when new Mailchimp Transactional subscribers are added
Mailchimp Transactional Email pricing: Free for new users for up to 500 emails. You can send 1 to 500,000 emails by purchasing 1-20 blocks at $20/block (each block is a credit for 25,000 emails). Enter your estimated number of emails per month in their pricing calculator to get an accurate cost.
If you want a similar pay-as-you-go option but don't use Mailchimp, ZeptoMail is a solid alternative (what Mailchimp calls "blocks," ZeptoMail calls "credits"). With ZeptoMail, your credits don't expire until six months after your purchase—which is great if the number of emails you need to send per month is uncertain. If you stick with Mailchimp, here are 6 ways to automate your email marketing with Mailchimp.
Best transactional email service for quick email delivery
Postmark specializes in only one service—transactional email—and does it well. It goes back to basics, focusing on core email sending.
Where Postmark stands out is its speedy email delivery: it aims to deliver all your emails within 10 seconds after you press send (they have a separate message stream for transactional emails to ensure timely delivery in the primary inbox). I was able to verify this while testing—the email I sent was delivered within 7 or 8 seconds of sending.
I found the setup instructions to be pretty straightforward. You simply choose the language or framework you want to use and get instructions for setting up. I chose to set up via WordPress plugin on my website and was done in under ten minutes. And their knowledge base felt much more approachable than the other apps on this list. Postmark also has several useful email templates available for specific use cases like welcome emails and password reset emails.
The analytics are pretty basic, which is representative of how Postmark is in general. Unlike the other apps on this list, it just doesn't offer many fancy bells and whistles. But if you need a reliable service provider that puts transactional email first, Postmark is a great choice.
One last note: ActiveCampaign recently acquired Postmark, and while Postmark remains available as a standalone product, ActiveCampaign users can now see a full picture of their customers and use just one application for all their email needs.
You can do more with your transactional email by using Postmark's Zapier integrations to do things like getting notified via Slack whenever an email bounces and even resend it.
Postmark pricing: Free for up to 100 emails per month. Paid plans begin at $15/month for 10,000 emails; $1.80 for each additional thousand emails.
Amazon SES is a good Postmark alternative if you need to send highly cost-effective transactional emails. But if Postmark's price is within your budget, I'd recommend choosing Postmark. Amazon SES doesn't have an easy-to-use UI or the convenient email templates. There's also no option to brand your emails or check time-stamped analytics—it's a barebones platform for sure.
Best transactional email service for a drag-and-drop email builder
MailerSend is a dream come true for non-tech teams and developers. Its drag-and-drop email builder is super intuitive, but there's also a rich text editor and HTML for developers who need it. There are also several transactional email templates, so you never have to start from scratch. I opted for the drag-and-drop email builder and found 30 templates—ranging from simple shipping notifications to complex ones like order-on-hold.
I tested the invoice receipt email template, and it was really quick to customize: adding and deleting various content blocks (social links, image, etc.), changing the background, modifying sections—it all took less than 15 minutes (given I had every detail and attachment available on my desktop).
The whole setup process was similarly easy: there are even domain authentication instructions that pop up as a chatbox as you finish setting up. I found that particularly helpful because there was a guide available for various domain providers, including GoDaddy, Wix, Namecheap, and more—meaning a user doesn't have to hunt for other resources outside the app. But even if something doesn't work, there's 24/7 email support in the free plan and 24/7 chat support in the paid plans.
They recently also introduced an email verification feature that allows you to run a fine-toothed comb through your email list and remove any emails that are misspelled, fake, spam, or simply inactive. This could be immensely helpful in validating your email list—and by extension, boosting your sender reputation and deliverability rate.
You can use MailerSend's Zapier integrations to automate your transactional emails. Get Slack notifications for hard bounced emails, send an email for refunded PayPal sales, or anything else you can think of to connect all your apps.
Get Slack notifications for new hard bounced MailerSend emails
Send MailerSend emails when new sales are refunded in PayPal
MailerSend pricing: Free for up to 12,000 emails per month. The premium plan begins at $25/month for 50,000 emails; $0.90 for an additional thousand emails.
Best transactional email service for thorough email analytics
SparkPost had the most impressive analytics that I saw in all my testing of transactional email apps. Its stats fall into four buckets: Report, Health Score, Spam Traps, and Engagement Recency. You can add metrics of your choice in the summary report to get a visual representation of data—like delayed rate, average delivery message size, policy rejections, and more. There's also the option to filter and compare different types of data (for example, comparing how your emails perform in Gmail versus Outlook).
While the numbers are plenty, they aren't difficult to understand. Even beginners on the team can use the data and run with it—most of them are self-explanatory if you have a basic understanding of email. Such detailed analytics might not be useful for every business, but if you're in a large company requiring a strong pulse on data, SparkPost would be the best choice for you. The setup process is also easy to navigate, even for a newbie. You can even join their Slack community and see what everyone else is up to.
One thing I should mention: many reviews complain of SparkPost's emails landing in spam and accounts getting suspended randomly. This can severely damage your sender reputation and relationship with your customers. If you do choose SparkPost, ensure to regularly check whether it's up and running properly.
To do more with SparkPost, connect it to Zapier, so you can do things like send emails when new files are added to Dropbox, when new Salesforce leads are created, or when anything else happens in one of the apps you use most.
Send email from SparkPost when a new file is added to Dropbox
Send email from SparkPost when new Salesforce leads are created
SparkPost pricing: Free for up to 500 emails/month. The Starter plan begins at $20/month for 50,000 emails; $1 for every additional thousand emails.
Which transactional email app should you use?
If you're already using an email marketing tool that offers a transactional email service, it's worth starting there. If that doesn't meet your needs, you'll want to look for an app whose primary focus is transactional email—give the apps on this list a try and see which fits your workflow best.
No matter which app you choose, you want your emails to be as effective as possible. Here are a few ideas to level up your transactional email app with automation. Then take a look at 3 ways to nurture customer relationships with email automation.
This article was originally published in January 2015 by Matthew Guay. The most recent update was in March 2023.