Sendgrid vs Mandrill vs Mailgun – How to Choose?

Are you just starting to work with email sending platforms or comparing solutions in order to switch? Which features matter the most? And how do you avoid getting lost in the wide variety of options? At Railsware we use several tools to communicate by email with our clients, candidates, Mailtrap users, and more. Let’s review some of the most popular email infrastructure services: Sendgrid, Mandrill, and Mailgun.

Types of emails: bulk and transactional

Before we move on to the detailed analysis of each service, it’s important to define their use cases.

Mailgun is an email service for developers designed for sending, receiving, and tracking emails. Sendgrid is a platform, which offers a set of options for both developers and marketers. Mandrill initially was a pure email delivery service but now it’s an add-on for the Mailchimp marketing platform. All of them offer services for both transactional and mass emails.

Bulk or mass email sending mostly relates to marketing and sales: you need to send one and the same message to a myriad of users at the same time. It can be a template with personalized data like names, locations, etc. Newsletters, special offers, and promotions are the most common examples of bulk email services usage.

The specific feature of these mass emails is the required “unsubscribe” option. Bulk emails are usually sent through SMTP servers.

Transactional emails are event-driven. Not you as a sender schedule message delivery but the user of your website or application performs some action, which triggers email sending. The user provides you with his or her email address and as a result, gets some response. It can be registration for your service (=> registration confirmation), contact or application form (=> an automated reply or an ebook), a purchase (=> order confirmation or an invoice). Another example is someone posting a comment on the blog – in this case, the author gets a notification.

Transactional emails can be sent both through SMTP relay or email API.

Bulk or transactional – it is the first high-level question you should answer when looking for the right provider. Whether you are a manager, marketer, developer, or DevOps, it’s important to think forward: is there any chance that I need additional capabilities in a month or two? What is the value I (read: my company) agree to pay for?

Email service features and parameters that really matter

Delivery speed, security, availability, and integrations are essential for transactional emails as well as spam rates, analytics, templates support, or/and design options matter for mass emails. These points are quite obvious but what hidden gems might we discover when going deeper?

Transactional emails priorities

The main three things we expect from transactional emails are deliverability, speed, and security. When we click “reset password”, we assume that the email with the cherished link will land in the primary section of our inbox in seconds. When we get the results of our medical tests, we need to be sure that this sensitive information will not become public. So, how is it provided?

1. Delivery infrastructure. Start your research with the delivery options. When you choose from the market leaders, most probably you can be sure that they rank for their reliability. Anyway, for better results, pay  attention to the following factors:
   • dedicated IP addresses for different purposes, maintaining IP reputation, and IP warming. These features have a direct impact on delivery speed and lower possibility of your messages going to spam.
   • email authentication standards to protect domain from spoofing:  SPF, DKIM, and DMARC validation.
   • API option. Sending emails through SMTP relay is a universal method matching most types of integration. When adding email functionality to your own application, a web API can be a more preferable option ensuring faster delivery.
2. Testing capabilities. You should always test your email before actually sending it. Here we are talking about the technical side, beyond the nice wording in a template and your customer needs in the center of your communication. The basic things to test are:
   • delivery. You can’t have a 100% guarantee of an email delivered to the particular inbox but you need to verify that your integration works correctly , “sender” and “receiver” addresses and headers look right, and so on.
   • content display (text and HTML). There are no unified images rendering standards for emails but you can test your message against possible issues in the most popular email clients and check if your markup looks as expected.
   • spam score. Additional tests for spam score and domain blacklisting will add just extra safety.
3. Ease of integration. It is more of your convenience but it is one of the first factors users mention about their experience with a new service. Delivery infrastructure is the “must” priority in our list but well-structured documentation with code samples and plugins availability are always a big plus.  
4. Analytics and reports. It goes without saying that monitoring the status of your emails is important. There are lots of dedicated services but having everything in one place is just easier to use and is more reliable in most cases.
5. Service uptime. Technical issues always have their place to be. So don’t forget to check the status page of the service of your choice. Check the history going back at least one year: how often did the site go down? How long did it take to fix it?

Bulk emails criteria

For marketing campaigns, priorities are similar but new things should be added here.

1. Delivery infrastructure. The note about reliability and security is still valid: you would prefer your emails landing in a main or at least promotional folder, not spam.
   • Scalability. You should be able to send your campaign to 1,000,000 recipients as successfully as to 100.
2. List management. You should be able to upload your list of recipients quickly and easy, edit, group, and tag it. This is quite obvious. You as a sender also earn your reputation: a high percentage of bounces and unsubscribes have a negative effect. Neglecting these rules is a direct way to the spam folder. How can the email service provider help?
   • Email verification. You should have the option to check if the email address exists without sending a message.
   • Opt-out. To comply with GDPR and any other privacy rules, your recipients should be able to easily unsubscribe from your messages.
3. Ease of integration. The main goal of a marketing campaign is to engage with customers, so we need more options for template creation and integration. Besides, the marketing specialist should be able to launch campaigns both with or without a developer’s or designer’s help.
4. Analytics and reports. You need to understand your user’s behavior on a deeper level. The more data you can get, the better: open, click, read rates, unsubscribe reasons, and sharing are the basic metrics to track.
5. Testing. The points are the same as for transactional emails. The main difference is that all marketing campaigns contain links, images, buttons, and other elements, which need to be carefully verified. Preview on different devices and mail clients, test campaigns will help to make sure that your recipient will get your email looking as beautiful as you designed it.

Now, with the understanding of what to look for in the email service providers, let’s check what each of them offers. Also, we’ve analyzed our own experience and reviewed users feedback on different websites like Capterra, G2Crowd, and Trust Radius to define the lists of pros and cons.

Sendgrid

Sendgrid was born in 2009, and since then has evolved into a powerful email marketing service. At the end of 2018, it was acquired by Twillo, the cloud communications platform.

Sendgrid offers solutions for both transactional and bulk emails sending along with a toolset for an instant building of marketing campaigns. This way, you can integrate it with your website or application, either another platform like WordPress or Drupal, or use as an independent tool.

The Sendgrid team emphasizes proven deliverability, confident scalability, and distinct email expertise as the specific strengths.

You will find tons of content on Sendgrid website. Most probably, you will get an answer to any of your questions but it can be easy to get lost at first.

Sendgrid offers the following products.

Email API (read: transactional emails)

You get the following capabilities:

1. SMTP API and Web API (REST)
2. Delivery and security
   • API and IP access management
   • both shared IP pools and a dedicated IP
   • SPF, DKIM, and DMARC record creation
   • email activity tracking and details-by-email API.
3. Analytics
   • event webhooks
   • real-time activity.
4. Transactional templates with HTML editing.
5. Integrations
   • cURL calls and libraries for Node.js, Ruby, Python, Go, PHP, Java, and C#
   • 3rd party plugins.
6. Testing
   • sandbox
   • sink domain.

Email marketing (read: bulk emails)

The most important features include:

1. Campaign builder with design editor (HTML and WYSIWYG) and templates.
2. Campaign management with flexible settings: scheduling, A/B testing, personalization.
3. Real-time analytics with key metrics and event webhooks for more customized tracking.
4. Sender authentication along with dedicated IPs and custom domain sending.
5. Email marketing automation, which now is in its beta.

Recently, Sendgrid has added display ads for Google, Facebook, and Instagram, which are connected to email marketing campaigns. The product is called Email Ads (now it’s in beta).

Here is a link to the Sendgrid status page where you can view the history of the incidents as well: http://status.sendgrid.com

What users like the most

1. Comprehensive documentation.
2. Sending speed and deliverability.
3. Easy to set up.
4. Seamless integrations.
5. Separate API keys when using for multiple systems.
6. Helpful support.

What users complain about the most

1. Confusing marketing campaign API.
2. Complicated or hard to navigate UI.
3. Lack of documentation on the third-party plugins integrations.
4. Just average level of reliability for shared IPs along with difficulties with checking their state.
5. Poor reputation management – you won’t be notified about problems.
6. Insufficient data tracking options. Especially, limited time for data storage (three days only) and the necessity to buy extra storage time.
7. Lack of features for transactional emails like weblinks or easy native unsubscribe.

We should add that Sendgrid is one of the most popular services, in particular due to its complex solutions. This way, it has gathered a great number of reviews and as a result – complains.

Mandrill

Mandrill is a transactional email API available for Mailchimp users. It was created as an independent service but in 2016 it was acquired by Mailchimp and turned into its paid add-on. This transition has caused waves of outrage from its users as it eliminated absolutely free billing plan. But now you can get all the advantages of the integrated email marketing platform.

In terms of information, such a division for transactional and marketing email campaigns makes it easier to clarify how the service works.

Mandrill offers the following:

1. SMTP API and Web API (RESTful)
2. Delivery and security
   • distributed infrastructure to provide seamless emails delivery
   • IP management: dedicated IP addresses, warm up, and pooling along with feedback loops
   • SPF and DKIM authentication
   • multiple domains.
3. Analytics
   • custom tracking and automated Google Analytics parameters
   • webhooks for integration with your own database
   • integration with your CRM with custom metadata.
4. Templates with HTML and automatic CSS inlining.
5. Powerful integrations
   • official APIs for curl, JSON, Python, PHP, Ruby, Node.js, and Dart
   • third-party plugins and modules for WordPress, Joomla, Magento, Drupal, and SPIP
   • inbound email routing.
6. Testing
   • test API key
   • testing stats.

Mandrill doesn’t show uptime statistics but has a dedicated Twitter account, which they call “Status”: https://twitter.com/mandrillapp/

As soon as you already have Mailchimp account for using Mandrill, you have the powerful email marketing platform at your disposal. See the full list of features here.

What users like the most

1. Reliability and high deliverability.
2. Easy to implement and use.
3. Flexible and comprehensive reporting.
4. Subaccounts management.
5. Transparent and clear IP and delivery information.
6. Thorough documentation.

What users complain about the most

1. Outdated interface.
2. Mailchimp dependence.
3. No free plan.
4. Difficult domain validation.
5. Poor support.

From our side we faced the blocking challenge when using Mandrill for transactional emails like signup confirmation or forgotten password. We haven’t received any warning or something else, so the reputation management complaints are valid for Mandrill as well. However, we had a positive experience with their support.

Mailgun

Mailgun is the email service for developers, it is what their key message says. You still can use it for both transactional and mass emails but it doesn’t offer independent functionality for marketers, like templates and media library.

Mailgun website will also offer you lots of information and enough space to get confused. Here is a list of main options. You won’t find the obvious splitting for different types of emails.

Transactional emails

1. SMTP relay and Web API (RESTful).
2. Delivery and security
   • SPF, DKIM, and DMARC customization
   • dedicated IPs
   • isolated sending domains
   • managed support and custom programs.
3. Analytics
   • various metrics, A/B testing, and tag comparison
   • webhooks and events
   • detailed log monitoring available up to 30 days.
4. Templates with HTML and automatic CSS inlining.
5. Powerful integrations
   • libraries for Python, Ruby, Java, Kotlin, Go, C#, PHP, Node.js, Luvit, cURL
   • inbound email routing
   • Mailgun has a number of integrations with 3rd party platforms and also recommends services which can be used to supplement its functionality.
6. Testing
   • test mode
   • email validation.

Special features for bulk emails

1. Scalability. It can handle up to 10,000,000 emails.
2. Email list management with email validation and segmentation.
3. Unsubscribe handling.
4. Personalization with Recipient Variables.

Here is a link to the Mailgun status page: https://status.mailgun.com/.

What users like the most

1. High deliverability
2. Great free tier
3. Easy integration
4. Effortless domain and DNS verification
5. Live chat support and great support overall, even for free users
6. Detailed error reporting
7. Email validation.

What users complain about the most

1. Outdated UI
2. Lack of testing options especially emails preview
3. Lack of IP statistics and risk when using shared IPs
4. Occasional delays
5. The complexity of the log search interface.

Sendgrid vs Mandrill vs Mailgun: basic features comparison

Feature	Sendgrid	Mandrill	Mailgun
Infrastructure	SMTP, Web API (REST)	SMTP, Web API (RESTful)	SMTP, Web API (RESTful)
Domain authentication	SPF, DKIM, DMARC	SPF, DKIM	SPF, DKIM, DMARC
Dedicated IP	paid plans only	for extra cost	for extra cost
IP management (dedicated IP required)	IP pools, warmup	IP pools, warmup	IP pools, warmup
ISP feedback loop data	yes	yes	yes
Event webhooks	yes	yes	yes
Subuser management	paid plans	yes	yes (except for Heroku and Rackspace accounts)
Email validation	no	no	yes
Transactional templates	yes	yes	yes
Testing	sandbox, sink domain	test API, test stats	test mode
Email designer UI	yes	yes (Mailchimp)	no
Mobile app	yes	yes	no

Pricing comparison

Sendgrid, Mandrill, and Mailgun are often compared regardless of their pretty different purpose and functionality. Let’s go to the pricing details to get the full picture. Small disclaimer here: each of these services has its own approach to pricing.

Sendgrid pricing is based not only on the sending volumes but also on features limits. Full features comparison is available on the pricing page: it is well-structured and easy to understand.

The main criteria for Mailgun pricing are the number of emails you send and the number of email validations. All features are available for all customers but more advanced plans provide some additional functionality as well. The Mailgun pricing page is minimalistic, so here is their blog post explaining how it works.

Mandrill costs depend solely on the email sending volumes. They offer you blocks of 25,000 emails. Don’t forget that a Mailchimp paid account is required as well.

Also, remember that for marketing campaigns in Sendgrid and Mailchimp, the list of subscribers matter. You will be charged not only for the number of emails you send but also for the number of subscribers you have.

Taking these attributes into account, let’s compare the costs of some basic and most demanded features.

Free emails sending, comparison

Provider	Sendgrid	Mandrill	Mailgun
Number of free emails	40,000 emails for your first 30 days	not available	5,000 emails for your first 3 months
Free emails time limit	30 days	not available	no
Forever free plan	100 emails/day	not available	no
Log retention	3 days	not available	5 days
24/7 support	no	not available	yes
Credit card required	no	not available	yes (otherwise you get additional limits: 5 verified domains of recipients only and 2 days log retention)

75,000 emails sending, comparison

Provider	Sendgrid	Mandrill	Mailgun
Monthly cost	$29.95	$60+$10 (minimum Mailchimp paid plan)	$32
Dedicated IP	not available	$29.95/month extra	$59/month extra
Log retention	3 days, or 30 days for $12 extra	30 days	5 days

250,000 emails sending, comparison

Provider	Sendgrid	Mandrill	Mailgun
Monthly cost	$142.45 (Essentials plan) / $199.95 (Pro plan)	$200 + $10 (minimum Mailchimp paid plan)	$165
Dedicated IP	not available (Essentials plan)/ included (Pro plan); additional IP is $30/month extra	$29.95/month extra	included (additional IP is $59/month extra)
Log retention	3 days, or 30 days for $40 extra	30 days	15 days

1,000,000 emails sending, comparison

Provider	Sendgrid	Mandrill	Mailgun
Monthly cost	$534.95	$720 + $10 (minimum Mailchimp paid plan)	$515
Dedicated IP	included Additional IP is $30/month extra	$29.95/month extra	included (additional IP is $59/month extra)
Log retention	3 days, or 30 days for $95 extra	30 days	15 days

So, which email service is right for you?

We have reviewed the two types of emails – bulk and transactional – along with the features essential for each of the tasks.

If you mostly deal with email sending through your own website or application and you don’t need the email marketing templates, then it might be reasonable to start with Mailgun. It partners with various platforms to make integrations easier. If you work with One Signal, Easy Sendy, Customer.io, Rackspace, Heroku, or Manifold, it can supplement their functionality well.

Mandrill is now indivisibly connected to Mailchimp, so if you already use this platform, you may find it rational to add their service to your list of tools.

Sendgrid offers flexible pricing and great quality as well. It was the first of these email services and is constantly improving and expanding its functionality. Check which options are pivotal for your current needs and make sure that they are included in the subscription plan of your choice.

Still, have doubts? It might be a good idea to check out customer stories. They can help you understand which type of business problems each of the providers copes with best.

Anyway, each of the services is praised for its ease of setup, so you should be able to switch between them effortlessly.