When should you use an email API?

Email APIs are an important tool with regards email deliverability, and there are many ways you can use them to boost your email operations. Read more...

In the worlds of email marketing and email technology, email APIs are a very important tool – they’re a big part of what we do here at Mailgun. However, if you have had little experience with them, email APIs may sound like just another confusing acronym to keep track of--like SEO, STO, and maybe even your ABCs (let’s be honest, Q doesn’t even sound like a real letter).

But never fear – in this article, we’ll tell you exactly what an email API is, when you can use it, and how your usage can benefit your email delivery goals. Let’s get started!

What is an email API?

The term API stands for Application Programming Interface. An API gives different platforms the ability to use tools from that API’s subject.


With email APIs, a desired platform – for example, a newsletter creation website – can use the capabilities of an email service provider within its own workspace.

The users of the newsletter website will not have to open up and use the email provider separately in order to send the newsletter. Instead, they can use an email API and its integrated functionality to send the newsletter directly from the website. Mailgun provides these APIs (as well as others like Logging and Mailing List APIs) for our external clients – when it comes to email, ease and efficiency are key.

All email APIs work in a similar way. When you use them, you can provide more consistent email messaging. An example of a Mailgun API is below.

When should I use an email API?

Email APIs are recommended for organizations that are able to build custom functionality into their chosen application. If you have this ability, email APIs have a lot of applicability. For example, they can help you reach your targeted audience through transactional emails and bulk mailing.

For example, if you work for a travel agency and a customer has scheduled a vacation through your service, you can integrate useful APIs into a confirmation email so the reader can do a number of things without leaving the inbox. The customer will be able to view their receipt, plane tickets, or itinerary through a link or other addition within the message. The customer will then have all of their needed information at their fingertips without having to reopen an extra website or app.

Special offers are another way that email APIs can be used with transactional messaging. By allowing a consumer to easily access a special deal or coupon, you remove potential obstacles to usage and the consumer has more of an incentive to take advantage of the offer.

Other common areas where email APIs are used include content management systems and social media applications. You can smoothly communicate an update on a website or blog to a list of email contacts using an API. You can also let a user know that they have a Facebook or Twitter notification, so they can easily respond to a message, update their profile, and more.

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When should I use SMTP?

SMTP (Simple Mail Transfer Protocol) is the method by which messages are transmitted between email servers across the Internet. It’s recommended for organizations that cannot add functionality to their applications, like an application developed for them by a third party. Like APIs, SMTP can be used for transactional and bulk emailing. To aid with integration, Mailgun provides multiple SMTP ports to meet the restrictions put in place by hosting providers and network admins.

SMTP port 587 is the most widely used port for email communication. However, one size does not always fit all for email communications. Mailgun uses several different SMTP ports for messaging, and the SMTP port that fits your organization best will depend on your specific messaging, recipients, and goals.

How do email APIs help deliverability?

Email APIs help in email deliverability by making messaging easier for both senders and recipients. An API ensures that a message is sent to a predetermined audience – usually through a list created by the sender – and eliminates the need for large numbers of time-consuming, manually generated messages.

The reduction of manual sending also ensures there’s fewer human errors, like mistyped email addresses or emails not going out when they need to. This improves the accuracy and consistency of sent email messages and leads to stronger levels of engagement with the targeted audience.

The role of APIs in improving deliverability and engagement is particularly important for organizations that communicate with large audiences. If one hundred customers request account password resets from a company in the span of an hour, that demand would be almost impossible to fill if the company attempted to manually create one hundred emails for its customers (think of the chocolate factory episode of I Love Lucy). There would likely be mistakes in the emails and, without an API, even customers who received the message might be confused about exactly which app or webpage to open up, and how to navigate to a password reset.

An email API allows customers to click the right link directly in their message and easily perform their desired action. This reduces error and improves customer experience.

Key takeaways about email API

Integrating email APIs into your existing platforms is a great way to make your customer communications faster and more efficient. When sending out large-scale messages and transactional emails, APIs will enable you to streamline important operations and consumer actions and take your organization to the next level.

Want more information on how Mailgun’s email APIs can help you? Check out our API reference guide!

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