What Are APIs and How Do They Work?


APIs are a key aspect of our digital world and allow us to engage in digital experiences on our phones and computers every day. Every time you use an app such as Facebook or Instagram, check the weather or send an instant message, you’re using an API. 

So what are APIs? API stands for Application Programming Interface, which enables communication between two applications. You can refer to the API definition as a messenger that pulls data to deliver a response to the provider you’re requesting it from.

Keep reading to learn more about Application Programming Interface, how it works, and its benefits.  

What are APIs? 

How are APIs used in the real world? When you use an application on your phone or search for something on the web, the application and web server retrieve data, interpret it, send a response and present it in a readable way.

To help you better understand what an API is and how an API works, let’s look at a real-life example

When searching for a flight, you have many options to pick from, including cities, dates, and times. Whether you are booking a flight via the airline's website or through a travel agency, you need to interact with the airline's website in order to access their database and view available seats, prices, flight schedules, etc. The application or website will therefore interface with the airline's API to retrieve the necessary information.

Think of the API as the interface that sends data from the application you are using to the airline's systems. The API receives the airline's response and passes it back to you. There is constant interaction between the application and the airline's systems, from seat selection through payment.

APIs do this for all applications and devices to create an efficient and connected experience. 

What are REST APIs?

What is a REST API? A REST API is often referred to as a RESTful API and is a representational state transfer architectural style that uses HTTP methods to perform functions like creating, reading, updating, and deleting records in a resource. 

A Restful API is comparable to a website running in a browser with the added functionality of built-in HTTP. 

REST technology uses less bandwidth than other technologies, making it the more preferred option. RESTful APIs can also be built into programming languages such as JavaScript or Python.

REST APIs allow users to connect and interact with cloud services in a distributed environment and are used by big names such as Amazon, Google, and Twitter. 


What are the Different Types of APIs?

Not every software integration is the same, meaning that not all APIs are the same. APIs are grouped together by their level of access, scope of use, and architecture. 

An API that is only meant for internal use will be different from an API that is meant for the public. 

Here are 4 types of web APIs:

1. Open APIs 

These APIs are open to the public and can be used by any developer. Therefore, Open APIs typically have low authorization and authentication measures. With Public APIs, you can share data openly and third parties can take advantage of the data it provides. 

2. Private APIs 

Private APIs, also known as Internal APIs, are not for third-party use. These Application Programming Interfaces are intended for use within a company and strictly for developers working for the company. They are hidden from the public and regarded as more secure and efficient. 

3. Partner APIs

Partner APIs are for external use, but they can only be used by those who have a business connection with the company providing the API. Access is limited so security measures are stronger with these APIs than with Open APIs. A lot of businesses choose this type of API to have greater control and more say in how their resources are used. 

4. Composite APIs 

Composite APIs combine two or more different APIs so developers can bundle API calls or requests and receive one response, resulting in fewer load times and faster systems. A Composite API is the way to go if you need data from multiple applications. 

What are the Benefits of APIs? 

The following are some advantages and benefits of Application Programming Interfaces.  

1. Efficiency 

With APIs, developers don’t have to create solutions from the ground up. For example, by allowing developers to reuse code in intricate yet repetitive operations, APIs enable developers to be more productive. The API outlines how to combine software components in a program. 

APIs also make it possible to distribute data more effectively when the material is automatically produced and made accessible on several channels at once.

2. Saves Costs 

APIs reduce costs by decreasing development efforts and the use of precious materials. Developers can use cost-effective APIs from their own internal APIs or third-party providers

APIs can decrease support expenses and shorten the time it takes to solve a problem. Effective APIs do this by providing concise error messages, mechanisms to track down problems, and documentation to aid in error prevention.

3. Wider Search and Personalization 

APIs deliver information and data to new audiences that can be customized and tailored to the user. Apps or other websites that users frequently visit can be used to provide information or services about your organization to those who do not visit your website.

4. Automation 

APIs allow machines to do the hard work rather than manual work by humans. They also allow companies to update workflows to be done in fewer steps, which leads to greater productivity. Additionally, you can efficiently and quickly publish new content and information across all platforms and make it available to your whole audience.

5. Integration 

Using APIs, your content may be readily included into your websites and applications. They guarantee a seamless user experience and current information. 

APIs enable various software to restructure their interrelationships in accordance with the unique requirements of your organization. By doing that, your business may improve results while spending less on development. 

What is API Testing?

API testing ensures that the Application Programming Interface meets its functionality, security, dependability, and performance requirements. In API testing, software is used to send messages to the API, obtain output, and record the system's response and delivery.

In the business logic of an application, where all transactions between the user interface and database levels occur, API testing is performed. The primary objectives of API testing are business logic analysis and the protection of application and data responses.

An API test is typically performed by submitting queries to one or more API endpoints and comparing the results to anticipated ones.

API testing has continued to be a crucial part of test automation and the CI/CD process for QA teams to uphold their dedication to quick release cycles and rapid modifications. API testing eliminates the requirement to keep scripts updated as the user interface of the application. 

Choose Katalon for API Testing

Katalon is an all-in-one test automation platform that can perform API testing for any team, at any level. Katalon makes it easy to create and run automated tests for your API.  

Our Application Programming Interface Testing is built to work with modern frameworks and requires minimal maintenance. Katalon supports all types of REST, SOAP/1.1 and SOAP/1.2 requests and can efficiently perform sustainable and productive testing through the use of data-driven testing techniques for increased test coverage and dependability. 

Learn more about how Katalon can help with API Testing here!