Mailgun Review (2024) – The Best Transactional Email Service for Developers?

Paul Newham 9 October 2024

Mailgun is an email delivery platform. Founded in 2010, it offers an API-based service aimed at developers. Teams add email sending to apps and websites with Mailgun. 

More than 150,000 customers use Mailgun, including plenty of well-known businesses. Microsoft, Slack, Reddit, Stripe, Booking.com, and Etsy are all customers. But it’s also popular with development teams at smaller companies. Mailgun is mostly used for transactional emails but can also send your marketing campaigns.

But is it the right email service for you? I gave it a spin to find out how it works and what it does best. 

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Mailgun’s most important features

Here are the main Mailgun features you should know about:

• Email API: Mailgun’s main feature is a RESTful email API built on HTTP. It lets you send and receive emails from any platform.
• SMTP: Mailgun also offers an SMTP relay service. This gives you simple, reliable bulk-sending. 
• Email Validation: Protects your sender reputation by weeding out fake, dormant, or incorrect email addresses.
• Inbox Placement Testing: Test where your emails land in different email services. Test results provide advice on how to pass spam filters and land your emails in inboxes.
• Email Logs: Mailgun tracks metrics for every email you send. You can use Logs to filter metrics and identify patterns in bounces, contacts unsubscribing, and delivery failures.

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Mailgun Review: Transactional Email API Service

Mailgun is built for reliable email delivery at high volumes. There’s a lot that goes into that. Not just making and sending emails. But also making sure deliverability is good and your sender reputation is protected.

Mailgun separates these into 2 products. Mailgun Send is all about creating and sending. This is also where you manage your sending domains, protocols, and contact lists. And get analytics for your sending performance.

Mailgun Optimize is the deliverability suite. Here you can validate email addresses and test deliverability. It also includes monitoring tools designed to protect sender reputation. 

Adding and verifying a domain

One of the first things Mailgun asks you to do is register a domain. This is to check you are who you say you are and cut out spam. In return, domain verification lifts send limits and enables tracking.

Domain are found in Mailgun Send under Sending > Domains.

Mailgun walks you through the adding and verification steps. You have to be the owner of the domain. At this stage you can also assign a dedicated IP address, if you have one.

If you don’t have a host or a domain, you can use a Mailgun sandbox domain to start with. But this is for testing purposes and has limited functionality. 

Setting up transactional emails in Mailgun

Once you’ve set up your domain, you can choose Mailgun’s email API or its SMTP relay to send emails.

The main benefit of API is simple, flexible connectivity to other software. So if you run an ecommerce site, email API lets you send from your store domain. This makes it easy to trigger transactional emails based on any customer actions.

SMTP relays are easier to set up and useful if API isn’t right for you. It requires less coding knowledge to configure and start sending.

Both the email API and SMTP take some configuring. Mailgun walks you through the process. But you need some knowledge of how to run code and set up ports. 

Creating and sending emails with Mailgun

With all the set-up done, it’s time to create your first transactional email. You can create your email templates in the Sending menu.

Mailgun isn’t an email marketing platform. So it doesn’t have the large selection of templates you’d expect from an email marketing service. But it does have a drag-and-drop editor for designing your emails. To use this, you start with simple outline templates. If you’re looking for more templates check out our collection of the best free responsive email templates.

You can also edit custom templates with HTML. But the drag-and-drop editor is an easy builder anyone can use. So I’ll focus on that.

If you’ve got any experience with drag-and-drop editors, Mailgun’s will feel very familiar. I found it very easy to use right away. Each template is divided into rows where you can add content blocks by dropping a block from the left sidebar.

Highlighting a row also gives you options to move, copy, and delete. From the Layouts menu, you can split rows into columns. 

To add content, you just click on a block in the editor. Clicking on different types of content blocks brings up different editing options. Here’s what the editing looks like in a text block:

You can add variables in the text editor to personalize your transactional emails. You put a variable like First Name in. Then Mailgun automatically adds the name associated with every email address.

Adding an image to your template works on the same principle. You click on an image block and the options appear. These are a bit limited. You can only add images via URL, for example. There is also very minimal image editing. 

This applies to the Mailgun editor in general. Styling is pretty basic. But you don’t need to go heavy on visual design with transactional emails. It’s more important that they serve their purpose. Ease of use is more important so you can build templates quickly and efficiently. Mailgun ticks that box.

Once you click save, your template is ready to send. But what you have created is a template. And Mailgun has a trick up its sleeve. A template API.

The template API provides a useful route for importing templates from other sources. No more having to copy and paste long HTML code. You can use POST requests to import the code using a few simple parameters.

Any templates you build in Mailgun are also added to the template API. You get documentation for your template in different programming languages and protocols. 

From here, you can also create different versions of the same template. This is particularly useful for A/B testing. You can build versions with different subject lines, headlines, images and more. Then you can use tags to compare performance in the analytics dashboard.

Mailgun doesn’t have any place to schedule or automate sending. Transactional emails are triggered by an action someone takes. Like a receipt or confirmation when someone completes an order. Finished templates are added to your website or app for sending using the API code. Or, for sending via SMTP, using a swaks script. Again, this is where programmer know-how is important with Mailgun.

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Email Parsing in Mailgun

Mailgun also offers tools for managing incoming mail. These are found in the Receiving tab in Mailgun Send.

These tools help you sort emails on arrival and choose different actions for them. It calls this building Routes for incoming emails. And it depends on a process called email parsing.

Parsing simply means using data in emails to trigger actions. The most obvious example is routing emails to a specific contact or department. This can be done based on who or where the email comes from. Or cues in its subject line or content.

Managing your email list in Mailgun

Mailgun is set up to send emails triggered by actions. But you can also create mailing lists for sending to groups of contacts. Mailgun’s list management has some unique features.

One is the size of the lists you can create. The maximum number of contacts in a Mailgun list is 2.5M. Another is that Mailgun creates lists using alias email addresses.

Alias addresses are used to forward mail from generic accounts to personal accounts. Mailgun uses them to forward emails to lots of addresses at once. All you do is set up a new email address at your domain. The Mailgun API can be used to add contacts automatically. For example, you could use it to build a list of everyone who buys certain types of products. You create an alias, add the API to the right page. And, with their permission, everyone who meets the trigger criteria gets added. 

You can also send mailing lists through different email services. You just have to create aliases using subdomains for each provider.

Mailgun lists can be huge. But you don’t have to send to whole lists at once, you can use tags to segment your contacts. Sending criteria in the API can be set to pick out specific tags. 

Mailgun is big on list hygiene. You’ll see a section called Suppressions. This logs all bounces, spam complaints, and unsubscribes. Mailgun won’t send to contacts that have unsubscribed or flagged you for sending spam. 

Testing emails in Mailgun

Mailgun has an impressive suite of email testing tools in the Optimize product. These focus on deliverability and inbox placement.

To run an inbox placement test, you have to create a seed list. This is simply a list of email addresses that Mailgun uses to conduct its tests. Ideally, you want to cover different email providers. That way Mailgun can test how your emails perform against different spam filters.

Mailgun doesn’t just tell you where your emails land. It also goes into detail about why. It reports on sender reputation, the content of your emails, and template designs. This gives you powerful insights for improving deliverability.

Verifying Emails with Mailgun

Mailgun claims bounce rates of under 0.5%. A big reason for that is that it offers email validation tools. Email validation checks every address on your list is working, authentic, and correct. It flags invalid or suspicious email addresses before sending. 

With Mailgun, you can check email addresses one by one or in bulk. You can also use the API to automatically verify new contacts. Check out our review of the best email verification tools to learn what email validation means and find the right platform.

Mailgun also has IP blocklist and spam trap monitoring to protect your sender reputation. 

Reporting and Analytics in Mailgun

I found a lot of crossover between Mailgun’s deliverability and reporting tools. Its suppression lists use 3 core email metrics: bounces, unsubscribes, and spam complaints. The other 2 are click rates and open rates.

This relationship between analytics and deliverability is even more obvious with Logs.

Mailgun has a dedicated API that tracks what happens to your emails. It does this by monitoring 9 events, including the 5 mentioned above. The others are delivered or failed to deliver. And accepted or rejected by the Mailgun system for sending.

The Logs page is where you see the results of the Events API tracking. The idea is to have full visibility of deliverability problems. You can narrow down searches with filters to identify trends in deliverability problems. And answer questions like: are there issues with a particular recipient or domain? Or even with a certain template?

On the Reporting page, you get the more conventional graph view of key metrics. This is a simple way to compare performance over time. There are 15 different metrics to choose from here. 

There’s a separate Analytics page dedicated to breaking down performance using tags. This gives you the freedom to segment and view data in any way you like.

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Mailgun Integrations and API

One of the big selling points of Mailgun is that it’s an API-first platform. Most of its core functions are built on APIs. And that means it’s ready to plug into any platform.

This is great for developers. But there is still a certain amount of heavy lifting around using APIs. To smooth things over, Mailgun also offers Zapier and Skyvia integrations to connect it with over 5000+ tools.

How Much Does Mailgun Cost? Pricing and Plans

Mailgun Send starts at $35 per month. This Foundation tier lets you send 50,000 emails a month via the email API or SMTP relay. You get full access to the template builder and all analytics. Including the Template and Event APIs. Inbound routing is also included. You can increase the send limit for $1 per 1,000 emails.

Mailgun Optimize starts at $49 per month. This includes 2,500 email address validations and 25 inbox placement tests. 

Mailgun Send also has a free sandbox you can try and set up. This lets you send 5,000 emails a month to 5 authorized email addresses via the sandbox domain.

See full pricing

Mailgun Pros and Cons

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Mailgun Customer Support

You’ll find Mailgun support options by clicking the ? in the header. Most of the emphasis is on self-help. There’s a lot of helpful support in the User Guides. The Documentation and Release Notes offer more technical support. These are important for using the various APIs.

You can search the various guides and documentation on the Support page. This is also where you can contact Mailgun’s support team. Email support is available on all plans. On the highest Scale tier, you can also get in touch via chat during office hours. Mailgun reviews from users often mention great chat support with issues solved promptly.

Is Mailgun the transactional email service for you?

So there’s my honest review of Mailgun. If you’re looking for a reliable email delivery platform for your site or app, Mailgun should be on your list. It’s ideal for transactional emails. And the fact that you can design templates for transactional emails in the app is a big plus. It offers email validation and inbox placement testing tools to increase deliverability rates.

The main thing to consider when choosing Mailgun is the fact that it’s aimed at developers. The API-based tools require some programming knowledge to set up and use effectively. The payoff is a very powerful and reliable service. You just need that level of expertise, especially for small businesses.

Ease of Use: 3 / 5
Value for Money: 4 / 5
Editor and templates: 3.5 / 5
Functionalities: 4.5 / 5
Deliverability: 5 / 5
Customer service: 4 / 5

Total score: 4 / 5

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Mailgun Frequently Asked Questions (FAQ)

Mailgun Alternatives

Mailgun vs. SMTP.com

The main difference between Mailgun and SMTP.com is scale. Mailgun is built for bulk sending at high volumes. SMTP.com goes even bigger. Mailgun send limits go up to 2.5 million a month before you have to ask for a bespoke package. SMTP.com has a ‘high senders’ tier that starts at 250 million emails a month!

Pricing packages aside, Mailgun and SMTP.com are very similar. SMTP.com also offers both email API and SMTP relay. And it has deliverability tools. One difference is that SMTP.com offers automated list hygiene checks. SMTP.com also offers a fully managed sending service. But Mailgun offers more flexibility with its choice of APIs. And it offers more Zapier and Skyvia integrations that are easy to integrate with other platforms. 

Mailgun vs. Sendgrid

Mailgun and Sendgrid are similar email delivery platforms at different price points. This reflects slightly different target audiences. Both offer a choice of email API and SMTP relay. Both claim excellent deliverability and come with email validation tools.

But Sendgrid comes out as the cheaper choice of the two. Its plans start at $19.95 a month for 50,000 emails. It also offers a separate suite of email marketing tools. Mailgun is targeted more at developers wanting to bake email into other platforms. It offers more customization if you have the know-how. And the parent company of Mailgun also has an email marketing tool called Mailjet. Check out our full Mailjet review to find out more about its features, pros, and cons.

Find more transactional email services in our review of the best SendGrid alternatives.

Mailgun vs. Elastic Email

A standout difference between Mailgun and Elastic Email is the starting price points. Elastic Email offers both an email API and SMTP relay. But its pricing starts at $9 for 10,000 emails. This makes it more accessible for SMEs. Find more tools to send email for free in our review of the best free SMTP servers.

Mailgun vs. Brevo

Brevo covers a much broader range of services than Mailgun. It does offer an email API and SMTP relay. But its main focus is email marketing and CRM. Brevo is one of the most popular email marketing services around. Standout features include marketing automation tools and a free plan with 300 emails a day to unlimited contacts. Its email API is also tied more closely to transactional emails. Read our full Brevo review to find out more about its features, pros, cons, and pricing.

About Paul Newham

Paul Newham is a content writer specialising in business blogging, report writing, software reviews, and online copywriting. He has 5+ years of email marketing, marketing automation and software review experience. He tested over 60 business software including email marketing tools, CRMs, outreach services, SMTP providers, email verification, and AI writing tools.
With a background in journalism and PR, he understands business content from both sides. And knows what makes for great, engaging copy, but also understands that for businesses, the written word is all about driving value.

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