What is an API and How Does it Work?

API stands for “Application Programming Interface,” and although you may not be familiar with what they are or how they work, you’ve used them before. Unlike a UI (user interface) which is designed for consumers to interact with, APIs are designed to communicate with different pieces of software or applications. At their core, they are a tool that allows two different applications to effectively communicate.  

Developers use APIs to build programs with already existing code, which makes it easier to create an effective program without reinventing the wheel. The API acts as a messenger to and from the developer’s application to the provider. This helps developers reduce their time creating code and spend more time developing niche solutions. 

 

How do APIs work?

For the end-user, an API may be indistinguishable from the application they are using. However, APIs are all over the web, from account logins to cart checkouts. Wherever they are used, there is quite a bit going on behind the scenes. In that process, APIs act as a messenger between the connected applications. 

APIs simplify the process for both the user and the service they’re trying to access. APIs will use a set of rules to help machines and applications talk to each other quickly and efficiently.  

While the importance of APIs is easy to overlook, after all we send messages electronically all the time, the process is more complicated than it might first appear. APIs not only connect applications but also act as a translator between different applications. Think of APIs less as mailmen, taking letters from one house to the other, and more as ferrymen adept at several languages taking passengers across a dangerous river. Connecting programs and applications in different languages is about as complicated as communicating with passengers in multiple languages while trying to ensure a boat isn’t swept away.  

 

How Do API Calls Work? 

An API call is a process by which a request for data is submitted and retrieved by the API. The process starts when the call is made to the API via its URI (Uniform Resource Identifier). When a valid request is made, the API will then transfer the call to the program with the relevant data. When it gets a response, it’ll then transfer the data to the party that requested it. 

 

API Examples 

Let’s look at several examples of how you may use APIs in your day to day to appreciate the diverse applications of Application Programming Interfaces: 

Airline Industry 

When booking a flight, you need to communicate with an airline’s site when you’re looking to travel. In return, the airline site needs to be able to communicate flights, times, and costs based on your request. Your application, whether it’s on the web on your computer or a mobile app on your phone, will reach the information in the airline’s database via an API. Your ferryman, the API, will float across the internet to make your request to the database, and then helpfully return with the answer in tow.


Ecommerce Industry 

The ecommerce industry uses APIs liberally as they give even small businesses access to quick, scalable, secure technology. APIs are used for everything from site searches to payments, allowing an ecommerce site to offer the kind of services once only available to large companies.  For example, an ecommerce site may use a login API to authenticate users or track login records to a site.  


Weather API 

Many systems that want to display weather information can do so with the use of a weather API. An API, like the National Weather Service API, connects information like weather forecasts and alerts to relevant applications. It’s likely that most of the information you get about the weather comes from an API that ferries data about your current location to a weather database and brings current information back to your device. 


Twitter API 

Twitter is a massively popular social media app that acts as a hub for current news, conversations, and opinions. Because of this popularity, the site has massive amounts of data about the global conversations being had minute to minute. A Twitter API can communicate these data insights to organizations in real-time based on the data gathered from these trending conversations. 


PayPal API 

The PayPal API is embedded into many ecommerce sites to offer an easy payment option for PayPal users. This API collects payment information from users and funnels it directly to PayPal, which means the merchant never interacts with your payment data. Because of the secure nature of API’s they are often used for secure payments. 


Types of API 

APIs have a wide range of use cases, from ecommerce payments to home screen weather displays. This range of functionality is partially due to the many different types of APIs that developers can utilize. These APIs are usually either REST APIs, built with Javascript, or SOAP APIs, built with XML.

Representational State Transfer (REST) APIs use Javascript Object Notation (JSON) to dictate the rules that allow applications to communicate. It’s the most popular kind of API and is used for web-based software. Simple Object Access Protocol (SOAP) APIs, on the other hand, use XML (Extensible Markup Language) to dictate the rules that allow applications to communicate. SOAP is less developer-friendly, and so it is not used as often as REST. 

Although APIs act as great building blocks for developers, not all of them are accessible to the public. Here are a few different types of APIs, and how they’re used: 
 

Web APIs 

Web APIs are built to provide services over the internet. The Twitter API, for example, uses a Web API to send data insights to organizations over the internet.  

Open APIs 

Open APIs have services that are designed to be used externally, whether they offer services for free or for sale. These APIs are usually offered to serve existing customers, monetize existing data, or connect users to a new product. 

Private APIs 

Private APIs are developed to be used as an internal resource, and as such are not used outside of the organization they were created. Sometimes their scope is extended to certain partners at which point they’re considered a Partner API.  



APIs serve a unique and important purpose in most everyday applications we use. While they are primarily used by developers, a general understanding of how they work is helpful to anyone looking to build a flexible solution for their business. If you’re looking for a flexible solution for your payments process, consider checking out our TokenEx Platform.  

 

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Topic(s): software development