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An application programming interface (API) allows two software applications to interact with one another through well-defined protocols and methods. Within the context of email, an email API allows applications to interact with an email service. This communication interface enables programmatic processes such as sending, receiving, and tracking emails.
The emergence of email APIs has significantly impacted how businesses digitally communicate with customers. Such programmatic emailing through email APIs reshapes how businesses handle email interactions by bringing automation and customizability.
In this guide, we’ll unpack email APIs, highlighting the functionality and benefits. Then, we’ll dive into practical steps—how to use email APIs, whether to build or buy, and what to look for in an email API.
Let’s start with some foundational concepts.
At its core, an email API acts as a liaison between an application and an email service provider (ESP). Rather than opening an email client, composing an email, specifying a recipient and a subject, and clicking Send, your software application can piece together the information needed for an outgoing email, then send a request with that information to an email API. The API accepts this request and communicates it to the email service, which subsequently sends the email.
As mentioned earlier, with an email API, you can programmatically handle sending, receiving, and tracking emails.
Let’s illustrate with a scenario. Suppose you have an online store and want to send a confirmation email to a customer immediately after they make a purchase. Without an email API, you would need to wait for a notification from your application that you received a new order. Then, you would open an email client to draft and send an order confirmation email to your customer. This might be acceptable if you receive one order every few days, but it’s neither scalable nor reliable. Consider the following:
With an email API, your application can send an API request to the email service to send the order confirmation email immediately following a purchase. Of course, the request will include all the relevant details—such as the customer’s email address, the subject line (“Your order has been confirmed!”), and the body of the email (with order summary and shipping details). However, the email API performs all this programmatically, fully automated.
By leveraging an email API, your business can ensure smooth and timely communication with your customers without manual intervention from you or your employees.
Email APIs can be feature-rich, and your specific need or use case may dictate the type of email API you ought to use. In general, we can categorize email APIs into the following main types:
Also worth mentioning are webhooks. While not technically an API, these play a critical role in the API ecosystem. A webhook is an HTTP request sent by an email service (typically to a URL you choose) whenever certain events occur, such as opens, clicks, bounces, and delivery confirmations. Your software application might have an API endpoint that could function as a webhook target. This allows you to process incoming webhook requests for tracking and monitoring email performance.
The right email API for you depends on your business requirements. Use the following scenarios to help point you in the right direction:
Although your unique business scenario will guide your choice, fortunately, most providers that offer email APIs will give you access to sending, receiving, and tracking APIs. The providers will likely have webhook functionality too.
The Simple Mail Transfer Protocol (SMTP), which has been around since the 1980s, is a communication protocol used by mail servers for sending and receiving email. Many email clients use SMTP for sending email messages to a mail server.
ESPs still use SMTP with their servers, and many give users the ability to communicate directly with those servers via SMTP. However, for sending emails programmatically, an email API is a more modern and versatile approach.
Businesses that communicate with customers digitally need efficiency, scalability, and customizability. This is where email APIs can benefit operations significantly. Here are the advantages of integrating an email API within your existing applications:
Now that we’ve outlined the potential benefits of using an email API, the next step is understanding how to effectively use one.
Getting started with using an email API requires three steps. Here, we’ll walk you through how to send your first email with the Twilio SendGrid Email API.
1. Sign up for a free SendGrid account.
2. Navigate to Settings ➤ API Keys after logging in. Click on Create API Key. Then, create a new API key with Full Access and give it a name. Copy your new API key (it should begin with SG) and put it somewhere safe for later access.
3. Use curl to send a request to SendGrid’s Mail Send API endpoint. Requests to SendGrid’s Email APIs use Bearer Authorization with your API key. A sample request looks like this:
Voilà. You’ve sent your first email through an email API. For a more detailed walk-through, read one of our getting started guides.
Using an email API offers several advantages. However, using an email API effectively and responsibly requires keeping the following key considerations in mind:
A typical question of organizations considering an API revolves around whether to use a prebuilt solution or build one. While building an API might seem appealing with the level of customization that it offers, this approach takes a considerable investment of time and engineering resources.
On the other hand, using a prebuilt API brings many advantages:
In light of these reasons, it’s clear why many organizations choose to purchase a prebuilt email API. Next, let’s look at the features to keep in mind when considering third-party email API services.
Choosing the right email API is a strategic decision, and the one you choose ought to align closely with your specific business needs. When considering your options, look for:
Switching from SMTP and direct email composition to a programmatic email API offers many benefits, including automation and scalability, that will far outweigh the effort you put into the transition. In addition, if you use Twilio SendGrid’s Email APIs, the process is straightforward.
After setting up your SendGrid account and obtaining an API key, choose whether to use SendGrid’s APIs directly (via HTTP requests) or leverage an SDK. SendGrid maintains official libraries for its mail-sending API for seven different languages:
When building an application with one of these languages, you’ll have a faster integration experience by using the language-specific libraries. However, if your development uses a language not listed above, you can always leverage an open-source library contributed by the SendGrid Community.
As we’ve explored in this guide, using an email API brings many benefits, including improved deliverability, security, and scalability. By opting to integrate a prebuilt solution like SendGrid, you reduce your development complexity while keeping your costs low.