The Marketer's Guide to API Integrations

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Jamie Juviler
Jamie Juviler


In marketing, you have a lot on your plate. Your team’s responsibilities likely include content creation and dissemination, email marketing, campaigns, and co-marketing, among other tasks. To accomplish these, I need a suite of software tools that work together seamlessly — and assembling this set is easier said than done.

man learns about api integration on a laptop

Thankfully, most marketing software today supports integrations. For many, this is all they need to know. Just find a service that’s compatible with your existing system, follow the instructions, and voilà, applications are integrated.

However, even if sheer curiosity isn’t enough, I think it’s valuable to understand how these integrations happen on the technical side. But don’t worry, you don’t need an engineering degree to get it. You just need to take a closer look at APIs, specifically API integrations.

In this post, I’ll cover the basics of what an API is and how it can be used. Then, I’ll delve into how APIs integrate with each other, and how you can build your own API integrations.

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How APIs Work

An application programming interface, or API, is the part of a software application that handles communications with other separate applications.

As a developer, I see an API as a tool that validates and processes requests from external clients for data within its native application. Essentially, a client asks for something, and then the API retrieves it from the database and sends it back to the client.

Just like I use a user interface to interact with an application, external software applications use an API to interact with the app. In this way, an API serves as a programming interface for developers.

APIs generally adhere to standardized protocols. In discussions about internet-based APIs, the term REST protocol often comes up. REST APIs form the bulk of web APIs today because they are straightforward for developers to integrate into their existing applications.

For example, when I’m building software that integrates with the social media platform X (formerly known as Twitter), I use the RESTful X API to retrieve information about a specific tweet (like its contents, likes, retweets, and post timestamp) or to post tweets. In both cases, Twitter’s API acts as a mediator between me and Twitter’s backend, granting me limited access to its internal data.

The above example also demonstrates a simple API integration, a process that is fundamental to today’s ecosystem of connected applications.

An API by itself isn’t very useful to me. Integrating that API with other software? That’s where the magic lies. Integrations help synthesize data from multiple sources. This enhances or completes an application's functionality.

Instead of getting a new app or making your development team add new features, APIs allow you to complete different tasks without a complete overhaul. You just need to make sure the API works and check that it’s properly integrated. Then, you can access that sweet functionality.

Today, most applications now leverage some form of API integration. Take, for example, how I use the Transit mobile app to navigate the train in Boston. Transit provides me with estimated arrival times. I can then decide if it’s time to walk or sprint for the bus.

The app gets this real-time data by integrating with the Massachusetts Bay Transportation Authority’s API. The app doesn’t compute arrival times itself. Instead, it displays the information provided by the MBTA’s web application.

I also see API integrations in many internal business tools. This process is everywhere — from when I add a file attachment in Gmail from Dropbox to when I receive a Slack notification about an event in the HubSpot CRM. This is a clear display of APIs working in tandem, sharing data seamlessly from different sources.

Almost anytime there's a need to share data between two independent applications, an API integration comes into play.

When to Use an API Integration

Expanding Product or Service Offerings

You may have a software or application that you love, but perhaps there’s one feature missing that would make it perfect. APIs can help! APIs can add new features or services to that app without you needing to dive into the source code.

For example, a fitness app could integrate a nutrition database API to provide diet-tracking features, or a finance app could use a stock market API to offer real-time stock trading capabilities.

Automating Business Processes

Have you ever been asked to gather data from a spreadsheet? I have. A half-hour in, my eyes start to glaze over, and all of the numbers look the same. Once that happens, I’m bound to make a mistake.

APIs can be used to automate these repetitive tasks. Not only does the process happen more quickly, but human errors decrease significantly.

For example, integrating an email service provider's API (like MailChimp or SendGrid) can automate email communications with customers. You just need to get your initial template right. The API can handle the rest.

Real-Time Data Synchronization

Let’s say I run an ecommerce business, and I want to see how many keychains I’ve sold at a given time. I could manually check once in the morning, once in the afternoon, and again before I log off. I can see the business I’ve done, but not when it happens.

APIs allow for real-time data sharing and synchronization between different systems. I then would be able to see exactly how many keychains I’ve sold once sales are made.

This can be helpful beyond sales. In the world of marketing, you can integrate APIs from analytics platforms like Google Analytics or data visualization tools. This helps your team gain deeper insights into customer behavior, website traffic, and overall performance.

How to Build an API Integration

Now that you know what API integrations can do, let’s dive into how to do it right. As a marketer, you won’t always be the one managing this process. However, knowing the steps will help you better understand API integration. Plus, you can be a hero if tech support is out of reach.

Regardless of your organization, successful API integration requires comprehensive planning, implementation, and testing.

How to Plan an API Integration

Adding an API may create a significant change for your business. So, start the process with a discussion where you clearly lay out how the API will benefit your team.

Sometimes, I identify a need before I know which application has the solution. In this case, I start by researching different API offerings, considering cost, capability, and ease of integration. I also build a plan that shows what I want to accomplish. This includes what data I’ll pull from the API and how that data will be stored in my systems.

Once I've decided which API to integrate, it’s time to determine how I’ll make the integration work. One option is a customized approach. Here, a developer creates an API from scratch. This solution offers the most control over the data flow between systems. However, this flexibility isn’t free. In fact, it’s usually the most expensive option.

So, like many companies today, I usually opt for an API that already exists. This tends to be more cost-effective and efficient.

API Integration Platforms

Adding functionality starts with an API integration platform, a software application designed to streamline the creation of API integrations. This tool offers a hub for all the APIs I need. Popular options include MuleSoft, IBM API Connect, Microsoft Azure, and Tray.

As a company grows and its software ecosystem evolves, the value of an API integration platform increases. You can adjust integrations as needed, replace outdated APIs with new ones, and automate tedious processes.

Additionally, the platform allows me to make multiple calls at once. Here, I can see how different integrated APIs act from a single location. This helps when I'm using different APIs for distinct purposes. The platform consolidates all my data into one place.

How to Test an API Integration

API Testing. Functional Testing. Performance Testing. Security Testing.

API integration testing makes sure that your API integrations work as expected — free from errors. After an API integration is complete, testing occurs before the application is used at scale. There are three types of testing you should be aware of.

First, there’s functional testing. This involves checking that each expected request receives the expected response. This includes normal, valid requests, as well as unexpected (but still valid) requests.

Next, there’s performance testing. This shows how API processes work when faced with a larger number of calls. Can the APIs that you use handle the number of requests you expect to send regularly, and are these requests processed quickly?

What if there's a spike in your requests? Can your API handle it? This is crucial to consider, especially as your business scales. The more data is sent between applications via your integrations, the more important performance testing becomes.

Finally, security testing ensures that all data transfers are safe between the client and API. Security testing checks whether requests are properly authenticated and authorized. You can also make sure data transfers are encrypted. If you want to learn more about what makes a secure API, check out our introduction to API security.

API testing can be performed with an API testing tool. These solutions simulate requests to an API and log the responses. Some API testing tools can even automate testing, which saves you time. There’s no need to create and send individual requests manually.

The Technology Behind Integrations

Cloud-based software almost never exists in isolation. Today’s software ecosystem has evolved thanks to integrations and, by extension, APIs. Whether you’re a tech startup or a large enterprise, the right software integrations let your organization operate more efficiently.

However, don’t just add integrations on a whim. You should identify your needs and choose the right API for what you’re looking for. Then, it’s time to plan how you’ll integrate your API into your system. As a marketer, this may be where you tap your tech team for help.

If you want to accelerate faster, you’ll need to integrate better.

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