Application Programming Interface (API)

An Application Programming Interface is an interface or communication protocol between different parts of a computer program intended to explain the implementation and sustaining of software. An API may be for a web-based system, operating system, database system, computer hardware, or software library.

API is the acronym for Application Programming Interface, which is a software intermediary that allows two applications to talk to each other. Each time you use an app like Facebook, send an instant message or check the weather on your phone, you’re using an API.

When you use an application on your mobile phone, the application connects to the Internet and sends data to a server. The server then regains that data, describes it, delivers the necessary actions and sends it back to your phone. The application then interprets that data and presents you with the information you wanted in a readable way. This is what an API is all of these results via API.

The Modern API

Over the years, what an “API” has often described any kind of universal connectivity interface to an application. More recently, however, the modern API has taken on some aspects that make them remarkably estimable and beneficial. Modern APIs adhere to standards (typically HTTP and REST), that are developer-friendly, easily attainable and understood broadly. They are handled more like products than code. They are designed for consumption for specific audiences (e.g., mobile developers), they are documented, and they are versioned in a way that users can have certain expectations of its maintenance and lifecycle. Because they are much more standardized, they have a much stronger system for security and governance, as well as controlled and managed for performance and scale. Like any other piece of productized software, the modern API has its software development lifecycle (SDLC) of designing, testing, building, managing, and versioning.  Also, modern APIs are well documented for consumption and versioning.

How does APIs work?

Imagine a waiter in a restaurant.  You, the customer, are sitting at the table with a menu of choices to order from, and the kitchen is the provider who will fulfill your order. You need a link to communicate your order to the kitchen and then to deliver your food back to your table. It can’t be the chef because she’s cooking in the kitchen. You need something to connect the customer who’s ordering food and the chef who prepares it.  That’s where the waiter or the API enters the picture. The waiter takes your order, delivers it to the kitchen, telling the kitchen what to do. It then delivers the response, in this case, the food, back to you. Moreover, if the API is designed correctly, hopefully, your order won’t crash!

 Types of API

There are numerous types of APIs. For example, you may have heard of Java APIs or interfaces within classes that let objects talk to each other in the Java programming language. Along with program-centric APIs, there are also Web APIs such as the Simple Object Access Protocol (SOAP), Remote Procedure Call (RPC), and perhaps the most popular at least in name Representational State Transfer (REST). There are 15,000 publicly available APIs, according to Programmable Web, and many thousands of more private APIs that companies use to expand their internal and external capabilities.


There are four main types of APIs:

  • Open APIs: Also known as Public API, there are no restrictions to access these types of APIs because they are publicly available.
  • Partner APIs: One needs specific rights or licenses to access this type of API because they are not available to the public.
  • Internal APIs: Also known as Private APIs, only internal systems expose this type of API, which is, therefore, less known and often meant for use inside the company. The company uses this type of API among the different internal teams to be able to improve its products and services.
  • Composite APIs: This type of API combines different data and service APIs. It is a sequence of tasks that run synchronously as a result of the execution and not at the request of a task. Its main uses are to speed up the process of execution and improve the performance of the listeners in the web interfaces.

Apart from the main web APIs, there are also web service APIs:

  • SOAP
  • REST


The Importance of APIs for Business

APIs, or application program interfaces, are vital tools for businesses in all industries. The importance of APIs from a technical standpoint, they allow the capabilities of one computer program to be used by another. They are a means by which two different programs can communicate. APIs enable companies to grow their businesses more quickly than ever before and represent an answer for the organizations that are currently spending more than $590 billion per year integrating disparate systems. Like the Web, which opened up the Internet’s potential, APIs are driving a new wave of innovation centered on sharing services. Organizations in all industries are looking to learn more about APIs and their potential to transform business processes.

There are several reasons why businesses like yours should consider launching APIs. They offer the potential to:

  • Increase revenue
  • Extend customer reach and value
  • Support sales and marketing activities
  • Stimulate business and technical innovation
  • Ease integration of backend data and applications




APIs are purpose-built to perform a specific function of allowing communication between applications. APIs have become an integral part of application development. They allow developers to quickly integrate specific functionality to their application or website. There are thousands of Public APIs on RapidAPI, find the one that will help power your next project on the RapidAPI Marketplace.