What is an API? How Different Types of API Work?

types of api

What is an API? How Different Types of API Work?

What is an API? How Different Types of API Work? 1200 628 Status200
Imagine you are standing in the airport lobby of New York and want to have accommodation there. You will not go to every hotel in the city to check if the ground floor one person bedroom is vacant or not. In the same way, you will not keep on visiting different hotels’ websites separately. Instead, any hotel booking app/website will allow you to browse and make a booking in the place with the desired facilities. Have you ever wondered that how can one website help you access the data from different vendors in one place? The process can be possible by using “APIs.” We can say API software is the intermediate software, an acronym for Application Programming Interface.  This article has explained everything that you need to know about an API, with types of API and its usage in JSON format.

What is an API?

What is an API

As defined above, API software is a service provided by an application to other external websites or applications to interchange data and information. We can say that API is a communication medium between two or more applications. API provides an SDK that a system can use to communicate with the business logic of another system. In other words, an API is a data layer that acts as a middleware for both client and server. Nowadays, the API layer is presented in JSON that any target system can interpret and use.

At first glance, it may appear like a complicated process but in fact widely dispersed in our surroundings. Every time you get a weather update on your phone, it is API. You place the order via the food delivery app, you are using API. These are the most common API examples.

How does API work?

Picture a waiter in a restaurant. His job is to get information from the customer. He, later on, passes that information to the chef working in the kitchen. After that, deliver the requested order to the customer sitting in the hall. Waiter worked as the intermediate communication channel.

In the same way, the API call begins with the user command. You request the application or website to do something. The application will pass that user-generated request to the pivotal API software to fetch the information from the webserver. In simple terms, the communication link initiated by your request (API call). That API call then runs and the response against your request is being delivered by another web server or software with the help of a middleman messenger (API software).

Real-life examples of API software:

Since now you know what API is. Here, we have discussed some real-life examples to portray a broader spectrum of its applications and API benefits.

Facebook/Gmail login:

Most of the websites allow sign up/in using a Google or Facebook account. In terms of development point of view, to trigger such logins, you need to use Google and Facebook’s API SDK in your codebase. They are open APIs, accessible free of cost with some decided terms and services. This is a common example of an API application.

Push notification & OTPs:

Push notifications are an audience engagement strategy. API software enables this service. Some push notification services are free, while many are not free and offer their budget plans. In the same way, companies also provide one-time pairing codes for the verification of credentials known as 2FA (2 Factor Authentication). In conclusion, this is also a prime example of API application usage.


Maps are usually displayed on websites to navigate directions (from point A to point B). It is also an API offered by Google maps.

Many of the online taxi apps utilize the same Google maps and places API. Every driving company is actually not working on satellites to get routes. In the same way, they simply fetch the data using API utilizing API benefits.

Payment gateways:

E-commerce people in business get money from different customers using various banks in a single account. API software also facilitates this service. Hence, using third party APIs of Stripe and PayPal is exactly how e-commerce stores trigger payments capturing.

Online travel services:

These applications aggregate all the information of departure, arrival, airlines, and bookings. They interact with the respective airlines, hotel, and commute related APIs that you want to book with and furnish the data to your screen in a readable form. Here again, you request an API call to get details from a travel service website. Then, API starts working. It runs and delivers relevant and updated information from the airline website to you at the travel service website.

Social media:

If you search for someone on Instagram or Facebook, it will use APIs to analyze the people with the name that you’d typed. In the same way, Twitter and other social media applications work.

Significance of API software:

Significance of API software

For businesses, knowing APIs sources and their execution is the core of getting web features implemented quickly and without the hustle of writing complicated codes (reinventing the wheel). Any modern business uses APIs to some extent to retrieve and manage data so as to make it easy for their customers to use. APIs also allow web developers to write code efficiently, quickly, and in a more robust manner. Hence, API software outsources this commodity by offering as a data warehouse that any system can use and integrate so as to make the best use of its functionality.

Open APIs: They are Public API with no limitations to access. Such API types are available for developers to implement and use for free.

Partner APIs: These APIs are accessible to the registered developers after an agreement. They are not available to the public. One can have access after making a deal or purchase.

Internal APIs: These are private APIs, limited to only for the internal organization usage. They are not accessible to anyone outside the company.

Composite APIs: On the contrary, these APIs are not supposed to run and deliver the information for any task request. Hence, they work with service APIs and data with synchronization to help boost the interface’s performance.

Web services & APIs:

A web service is a network-based service that applies an address on the World Wide Web (www) in the form of a URL to grant passage to the services. It fulfills a task and provides API an interface allowing data retrieval and functionality from another application. They can apply any web protocols involving REST, SOAP, presenting data in the form of XML or JSON. In the broader term, all web services can be APIs, but not all APIs are web services.

Types of APIs:

We can categorize API types as REST, RPC, GraphQL and SOAP.

SOAP is an acronym for Simple Object Access Protocol. It is a messaging protocol that executes on HTTP protocol and presents the data in the form of XML.

what is XML

Any third party client then follows the SOAP standards in order to integrate this API type into itself. A standard SOAP response contains a data packet known as Envelope, containing the data Header and data Body. It allows text, numbers, and different input formats with strenuous conditions and very convincing security standards.

RPC is an acronym for Remote Procedure Call. The oldest and simplest class of API with the benefit of involving varied services or applications. They can be both, XML coupled or JSON coded. To implement this mechanism, one application calls for a trigger of a specific piece of functionality on a third party system. Then, the client application gets the response from the third party system and presents it in a human-readable format. 

What is REST APIs?

REST is an acronym for Representational State Transfer. It is a collection of definite principles. Moreover, it is user-friendly. It provides smooth connectivity of server and client with straightforward compositional style. The main reason for its wide popularity is due to its easy to use interface, quick creation, and parsing time. Many famous websites, such as Facebook, Netflix, use REST APIs. Rest APIs deal with the Post, Patch, Delete, and Get methods. Before explaining them, you should have an idea of the JSON format.

How JSON APIs work?

JavaScript object notation is the web service API protocol in RESTful APIs. It is the standard text-based format. JSON’s format sends information to the database by using this format. The role of JSON is similar to XML. But, the main advantage it beholds is the lightweight format.

JSON houses the data in the form of Key-Value pairs. The data types that it supports are,

– A number (Can be integer or decimal)

– A string (to support Text)

– A Boolean (to support conditional data types such as True and False)

– An object (to support JSON Object)

– An Array (to support array data structures)

– Null (to store void data)

As per its syntax, if we want to present the employer name as an API response. In JSON format, it will be written as;





How JSON APIs work

Methods of Rest APIs:

Most of the time these REST methods of API are used to perform specific actions. Sometimes, developers call them verbs or requests. Details of the types of API are below:


The post is defined to create or override the information. Mainly, the post makes a new resource with an already existing parent’s association as a subordinate. It assigns a unique resource URL and ID to it.

201 HTTP statuses indicate the successful creation on the origin server. It leads to the new resource and location header. 200 is an OK response, meaning that the API call went successfully. On the contrary, 204 depicts no content. The POST request is non-idempotent.


Get request only works with the representation of data or information. It does not change the state and modify it but gives a preview of data.

Moreover, they are idempotent. It means that identical requests multiple times will not alter the results. Similarly, it will preview the same (available) result every time.

Firstly, HTTP response code 200 depicts the OK content.

After that, if the resource is not in preview to the server, it will give the error code 404. This code will be shown in both cases if the content is not available (Not Found) or when the request is not accurately made (Bad Request).


Put API calls are a subset of Post. Developers send these requests to already existing resources to update them partially or completely, or to create the resource. Unlikely, but requests are idempotent. While the post API method keeps on creating the same resource when called multiple times. In the same way, but requests are performed on a single resource, while Post requests apply command that results in the creation of new data resources.

HTTP code 201 depicts the OK, as the modification in the resource is complete. When the server responds with code 204, it identifies as No Content is available there. These responses do not generate caches.


As the name reflects, this method is the type of APIs that deletes the resource from a definite location. Certainly, it should be used with caution, as it’ll remove the collection of resources from the database. Same HTTP code 200 will depict OK. On the contrary, 404 will appear if the content or ID is invalid or not available. (Not found)


This type of API method is in use to execute a partial modification in the resource. As the put method will update the complete resource entity, developers will prefer the patch to make partial updates instead of entirely replacing it.

In simple words, while using JSON, you are creating content by post or put request. Get command will retrieve the user. Moreover, data preview will appear by the Get command. Then, you can partially modify it by the Patch method. In the end, you can altogether remove the content/user by the Delete method. We can test all of the processes. HTTP code 200 will indicate the OK for every resource command.


APIs are vital for database-driven systems. In our routine life, we have APIs benefits in all our surroundings. Everything around us is updating. We are getting modernized in our businesses and everyday life. As a result, to move with the fast pace of market competition, every business needs advanced tools and technology. Most importantly, APIs help marketers by offering innovative digital marketing strategies.

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