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What to Look for When Choosing an Email API Service

Angela Stringfellow

Last updated on

Email is among the most common digital communication tools used to reach customers. The ubiquity and common standards for email make it a desirable channel for digital marketing campaigns. In addition to marketing messages, businesses also use email to send transactional messages. Given the wide range of potential uses for email, it’s no surprise that an estimated 306.4 billion emails were sent and received each day in 2020.

What are Email APIs?

Emails can be sent from any server or computer using Simple Mail Transfer Protocol (SMTP). But sending emails in bulk and in an automated fashion requires elaborate infrastructure and extensive expertise. It is challenging and time-consuming for each individual company to build an email system within.

Businesses can make use of mail APIs (application programming interfaces). Email APIs give developers access to the features and functionality of an email platform. These API providers take care of all operational aspects of sending emails en masse, and many of these API solutions are plug-and-play. There are a variety of factors to consider when choosing an email API service. Let’s take a look at a few of the most important considerations.

Email Deliverability

Email deliverability is the most critical factor in any email campaign. All email providers have a service to sort the incoming mails into an inbox and a spam folder. The emails that go into the spam folder typically are never read by the recipient even though the email has reached the destination server. Many factors go into determining whether an email ends up in the spam folder, such as:

  • Sending emails without permission from the user
  • Using SMTP servers that have a reputation of sending spam emails
  • Negative engagement from the recipient
  • High bounce rate
  • No easy option to unsubscribe from emails
  • Bad email design

Most of the factors mentioned above are affected by the reputation of the email API providers. Choosing an API provider that cannot manage their infrastructure to ensure maximum deliverability is a big mistake.


When a business has to send a few hundred emails at a time, the speed of delivery of email API is inconsequential. But when you need to send millions of emails, a slow service will delay the email for days. This is not great for time-sensitive marketing campaigns and transactional emails.

An email API service should have the bandwidth and capacity to send a large volume of emails within a few seconds. Backlogs and bottlenecks caused by your email API can result in the loss of potential sales and customer alienation. Ask about the delivery speed of the email API services you’re considering and verify it before choosing a service.


Cybersecurity is a major concern for organizations of all sizes. A sizable number of cyberattacks exploit email vulnerabilities to gain unauthorized access to sensitive data and systems. Choosing an email API service that uses superior security practices like encryption is crucial for protecting business and customer data.


With APIs, the various triggers for sending emails and the process of sending the emails are activated by computer code. But marketers also make use of email APIs to build campaigns, and they may not be adept at using highly technical services.  

Choose an email API that has a simple UI layer that can be easily understood by anyone. Programmed logic should be simple to understand on the interface. This is the basic factor for API usability. If the UI interface of the API service can be used to create email delivery logic, that’s a nice bonus feature. Such a service can be used by marketers without coding knowledge and without the help of developers.


Sending emails without the ability to measure the outcome and efficacy isn’t the right way to go. Analyzing your email campaign data is essential for improving future campaigns. Analytics can be used to test various email formats and titles to identify the best-performing methodologies.

Many email API services offer just the core technology without analytics capabilities. Some don’t even collect any data regarding campaigns. Choose the service that has a robust suite of analytics tools to provide meaningful insights into campaign performance. At the very least, an email API has to collect and store data that can be used on another analytics platform.


Price is a key determinant in any business decision, and choosing an email API service is no different. However, you shouldn’t choose an email API service based on price alone, as the cheapest service may lack other valuable features. Price should be balanced along with the other factors that go into email API decision-making.

Email APIs make the task of sending emails easier. But choosing the right API can help to ensure the success of your email campaigns. Carefully weighing all the factors mentioned above will help you choose the best email API for your needs.
An inbox feature for applications can bypass the need to send emails to users. Push messages and transactional messages can be directly sent to the inbox of the application without relying on a third-party email service. MagicBell’s easy to implement and intuitive inbox solution can be integrated to any application within half an hour.