What is API?

An application programming interface (API) essentially allows two applications to communicate with each other. If you're not sure exactly what APIs are, how they work, or how to create one, the following guide to APIs will make things clear.

What Is an Application Programming Interface (API)?

To understand how APIs work and what they can do, it's important to define the application programming interface (API). Specifically, APIs consist of certain protocols and definitions that give two software components the ability to connect. In the acronym, there are two main components with their own API meaning. These include:

• Application — Any type of software that performs a particular desired function.
• Interface — This helps identify the specific ways in which two applications communicate with each other based on the definitions and protocols in place.

Whenever you use an app of any kind, you're using some type of API to perform specific functionality, whether you're using instant messaging in a social media app or checking your financial data in a banking app.

Brief History of APIs

The application programming interface (API) essentially began with the introduction of the world wide web, as businesses sought ways to improve commerce capabilities online. As such, early APIs enabled websites to connect with consumers via third-party resellers and partners. 

APIs stemmed from earlier attempts at software integration, including electronic data interchange (EDI). The first EDI came into fruition in the early 1970s when London's Heathrow Airport used it to transfer information to customs processing systems more directly than it could with previous methods.

Today, there are many APIs that power a wide range of applications for all types of users. They give everyone from the average consumer to corporate executives the tools they need to perform nearly any task imaginable.

What Is a Remote API?

A remote application programming interface (API) relies on communications with an external source to influence the API's resources. The majority of web APIs are remote and work according to web standards. Using a remote API, it's possible to provide the same defined standards of interaction across all instances of an application, regardless of the system using it. This gives every user the same experience when interacting with the application.

How an API Works

The application programming interface (API) gives different types of software the ability to communicate with each other, with the API acting as an interface that an application or system can interact with, much like how end users interact with an application's interface. 

In most cases, web APIs are fixed in place between the web server and the application. When the user interacts with an application's interface, the app must then communicate through an API to facilitate the desired action. APIs specifically communicate with the web server to request the necessary data. 

APIs also use an application programming interface key, which is a code that helps identify a user or application to authenticate them. They're most commonly used to authenticate an API project. There are many potential uses for API keys, depending on the application and system.

Why We Need APIs

The application programming interface (API) is critical today because it enables users to get the most from the devices and applications they use every day. It also enables businesses to remain competitive and stay connected online. 

One of the biggest reasons for the rise of APIs has been the development of devices such as smartphones, Internet of Things (IoT) devices, and wearables of all kinds. Consumers want to be able to use these devices to their full potential, which APIs help achieve. At the same time, many companies develop APIs and make them available to the public, which ensures they remain both competitive and relevant.

Additionally, developers benefit from APIs seeing as they don't have to write extensive code. Instead, they extract the services and data they need for their applications from other external sources, which saves them time and energy. In turn, they can spend less time worrying about integrating functionality and more time developing a solid app that users will love.

Common API Examples

There are many types of application programming interface (API) out there that we use on a daily basis to perform a wide array of functions. Some examples of frequently used APIs include:

Twitter Bots

There are many bot accounts on websites like Twitter that automatically interact with these platforms. For example, Twitter's Netflix Bot automatically tweets about new Netflix content as soon as it's released, which lets users know when a new show or film is on the platform.

Weather Snippets

Weather apps often rely on weather snippet APIs to update local weather data for users. With the help of these APIs, people can check apps and smart devices to see what the temperature is, along with humidity levels, forecasts, and weather conditions.

Trip Booking

Many travel websites and applications also rely on travel APIs to pull data about everything from flight departures to hotel vacancies. These APIs can help travelers easily find the best flights and places to stay during their travels. The API then automatically relays the user's input and requests to hotels and airlines, eliminating inefficient manual processes.

These are simply a few of the many potential uses for APIs out there. Nearly every type of application and website has a use for many APIs to make them fully functional and easy to use.

Common Types of APIs

You'll find many types of APIs for many functions. The following are some of the most common API types and their purpose:

Web APIs

These apps operate using Hypertext Transfer Protocol (HTTP). Using web APIs, users can perform many functions within a browser. For instance, they can use web APIs to view web pages and receive notifications from websites. These APIs come in four main types, including open, internal, partner, and composite APIs.

Open APIs

These are APIs that developers can use, with minimal authorization and authentication measures in most cases. They also tend to limit the number of assets that developers can access. Businesses benefit from making APIs available to the public by encouraging developers and businesses to connect with the third-party app that actually owns the API. This increases the overall value of the API.

Internal APIs

These APIs aren't intended to allow for public access and use. They're strictly for helping employees within the company perform various tasks. Typically, they help increase the efficiency of workflows by simplifying data transfers. Their private nature makes them more secure than open APIs, but companies often make their internal APIs available to the public at some point.

Partner APIs

A partner API is similar to an open API, only companies restrict access to business partners instead of making them publicly available. This gives companies more access to control and the use of the API. As a result, they're also more secure than open APIs, albeit not quite as secure as internal APIs.

Composite APIs

These are APIs comprising several types of APIs that enable developers to pull data from various sources and applications. Composite APIs are ideal if you need to make multiple requests by automating the process.

How to Create an API

If you want to develop your own API, there are several steps you can take. The basic steps entail:

1. Gauging your requirements — The first step will involve determining the specific requirements that the API can meet. To do so, you need to consider what audience your API is for, which could include consumers, your company's employees, both, or others. What do they need and want from your API?
2. Design the API — The next phase will entail designing the API based on your audience's requirements. You can approach this in a few different ways. For instance, you could convert an existing resource into an API or design the interface before developing the backend.
3. Develop the API — Once you've designed your API, you can begin developing it. During this phase, your API should have a specific name and helpful description, along with specifics around the function of the API. You also need to consider security measures and the capabilities of the API when it comes to behaviors such as caching and rate limiting.
4. Test the API — After development comes testing. This will help gauge the effectiveness and overall functionality of the API before releasing it.
5. Publish the API — If the API passes initial testing, you can then release it internally or openly. You can properly deploy your API using an API gateway to host it.