JSON Interview Questions

Are you searching for the right stuff that would help you crack a JSON Interview? Well! Stay tuned here. This blog has been designed for Javascript career aspirants like you. We have curated the most important interview questions and answers of JSON. In this blog, we have provided the latest JSON Questions 2023 for Freshers and Experienced, which will help you to land your dream job.

JavaScript Object Notation, JSON, is a syntax that helps exchange and store the data. This one is a language-independent data format and is an open standard file format. Mainly, JSON is based on JavaScript and uses programming conventions that are used in other programs, such as Python, Perl, C#, C++, C and more.

Now that you’re preparing for a JSON interview, being familiar with the latest interview questions can help you to a great extent in sharpening your knowledge. To help you out with this, we’ve compiled some of the latest basic JSON interview questions and advanced JSON interview questions. Let’s have a read ahead.

We have categorized JSON Interview Questions into 2 types, They are:

Frequently Asked JSON Interview Questions

  1. What exactly are JSON objects?
  2. Explain what JSON-RPC and JSON Parser are
  3. What are some of the applications of JSON?
  4. Can you tell me what JSON's MIME type is?
  5. Describe the benefits and characteristics of JSON in detail
  6. What advantages does JSON have over XML?
  7. What are JSONP's limitations?
  8. Why is JSON used in Android?
  9. What is JSON Formatter, and how does it work?
  10. What is the difference between Serialisation and Deserialisation in JSON?

JSON Interview Questions - For Freshers

1. What exactly is JSON?

JSON is a faster and more accessible data exchange format. JSON (JavaScript Object Notation) is a platform and language-independent data format. JSON is a wire protocol that specifies a data format for data exchange/communication between processes/applications.

2. What exactly are JSON objects?

A collection of name/value pairs is referred to as an object. An object in JSON starts with a left brace and ends with a right brace. A colon follows each name, and the name/value pairs are separated by a comma (comma). 

3. How do you convert a JSON text to a JavaScript object?

JSON is widely used to collect JSON data from a web server in a file or an HTTP request, convert the JSON data to JavaScript, and display the data on a web page. 

4. Why is it necessary to utilise JSON instead of XML?

  • JSON objects are typed JSON types: Number, Array, Boolean, and String are all sorts of data. It is faster and lighter than XML since XML data is typeless over the wire.
  • In XML, everything is a string.
  • Data is readily available as a JSON object in your JavaScript.
  • You have to read from an object property in your JavaScript code to get values.

5. Explain what JSON-RPC and JSON Parser are.

JSON RPC is a basic remote procedure call protocol similar to XML-RPC but uses the lightweight JSON format instead of XML. JSON Parser is a tool for parsing JSON data. JavaScript, PHP, and jQuery can parse it.   Mentioning the JSON file extension JSON is a type of data format.

6. Which function is used to turn a JSON string into an object?

 The "eval" function turns JSON text into an object.

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7. What are the data types supported by JSON?

JSON supports a variety of data formats.

  • Number 
  • String 
  • Boolean 
  • Array 
  • Object 
  • Null

8. What is the function of JSON.stringify?

JSON.stringify() converts an object to JSON text and saves the result as a string.

9. Mention the PHP function that is used to encode JSON.

To encode JSON in PHP, use the json_encode () function. This function returns a value's JSON representation; if it fails, it returns false.

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10. What steps are involved in converting a string to a JSON Array?

First, use the JSON. Parse() method to convert the JSON text to a JavaScript object, and then use the push() method to extract the object's values and push them into the array. 

11. What exactly are JSON files?

 JSON files have  the ".json" file extension. "application/json" is the MIME type for JSON text.

12. What are some of the applications of JSON?

JSON is used in multiple ways:

  • JSON is used when creating JavaScript applications, such as browser extensions and websites.
  • JSON is a serialisation and transmission standard for structured data across a network connection.
  • Web services and APIs use the JSON format to deliver public data.

13. What are the disadvantages of JSON?

  • JSON  has several drawbacks.
  • There is no type of definition in it.
  • It's missing a DTD 

14. Can you tell me what JSON's MIME type is?

 "application/json" is the MIME type for JSON text.

15. Explain what JSONP is.?

JSONP is an abbreviation for JSON with padding. It's a technique for getting around cross-domain rules in web browsers. In other words, when transmitting JSON replies from multiple domains from the client, JSONP is a straightforward approach to cope with browser constraints.

16. Explain the distinction between JSON and JSONP.

JSON: JSON is a basic data format for exchanging information across systems.
JSONP is a way of using the JSON format with cross-domain ajax calls while avoiding the same-origin policy issue.

17. Do all programming languages and platforms support JSON?

Yes, JSON is supported by most technologies that work with data transmission between systems. JSON is supported by practically all computer languages and platforms due to its text-based nature. Javascript, C, C++, C#, Perl, Java, Python, PHP, and other languages are among them.

18. What exactly are JSON objects?

A set of key-value pairs is what defines an object. A left brace "precedes a JSON string and is followed by another right brace ". A colon ":" follows each key, and a comma separates the key-value pairs ". A JSON object is a collection of keys and their values organised in a pre-defined JSON structure.

19. What is the JSON file's extension?

The extension for a JSON file is ".json." A JSON file can be viewed or changed with any text editor, such as notepad or notepad++ because it is text-based.

To Know More, Visit Our Article on the Most Common Asked Javascript Interview Questions.

20. Describe the benefits and characteristics of JSON in detail.

The JSON structure has several benefits over other data transfer formats. They are as follows:

  • The nature of the product is simple to use and quick. Data parsing is simple with the JSON syntax, and implementation is faster. JSON's lightweight structure allows it to respond significantly more quickly.
  • Multiple operating systems and browsers are supported. This allows the JSON format to be adapted to various systems without requiring additional effort to ensure platform compatibility.
  • Integers, doubles, strings, Booleans, and more data types.

JSON Interview Questions - For Experienced

21. What are the applications of JSON?

JSON is used in multiple ways:

  • JSON is used when creating JavaScript applications, such as browser extensions and websites.
  • JSON is a serialisation and transmission standard for structured data across a network connection.
  • The JSON format offers public data via web services and APIs.

22. What are the rules of JSON syntax?

Several rules describe the structure of JSON. These are the following:

  • The data in a JSON file is organised into key-value pairs. The key is on the left, while the data on the right represents value. The separation of the key and the value is denoted by a  colon ":" 
  • A comma is used to separate each set of key-value pairs from the other pair.
  • The JSON objects are defined using curly brackets. The left curly brace "denotes the beginning of an object”, while the right curly brace "denotes the end of an object”.
  • The square brackets "[]" define arrays within a JSON object.

23. What advantages does JSON have over XML?

JSON is a data communication format. It has several advantages over XML that should assist it in displacing XML as the most widely used data transfer standard.

  • XML is heavier and slower than JSON.
  • Object types are defined in JSON. However, they are not defined in XML. Different object types exist in JSON for different data types, such as string, integer, Boolean, array, etc. The string is the only data type that all XML objects are classified as.
  • JavaScript makes it simple to read JSON data as a JSON object. On the other hand, the XML data must be parsed and assigned to variables utilising APIs. Getting information from a JSON file is as simple as reading an object in JavaScript.
  • JSON is more accessible and helpful than XML because of its lightweight text-based nature.

24. What do JSON and XML have in common?

JSON and XML have a lot of similarities. It's as follows:

  • JSON and XML are both used when transferring data between systems.
  • JSON and XML are both human-readable and have a simple structure.
  • Both are language agnostic.
  • JSON and XML support nested or hierarchical structures.
  • Both of them are simple to parse using a variety of programming languages.
  • Both these structures support Unicode.

25. What are the different browsers that support JSON?

JSON support is built into nearly every new browser version. JSON is supported by many browsers, including Internet Explorer, Chrome, Safari, and Mozilla Firefox.

26. What is the purpose of the NewtonSoft Net framework?

  • Json.net, often known as Newtonsoft, is a popular.NET framework for executing JSON operations.
  • It uses internal framework components like JArray, JValue, and JObject to allow users to parse, create, change, and query JSON.
  • It offers a more convenient way to query JSON using XPath-like syntax.
  • Its excellent JSON serialiser allows users to serialise and de-serialise an object in   .net.
  • It outperforms current serialises in terms of speed.
  • Simple and easy to use.
  • It can also convert XML to JSON or the other way around.

27. Is there any possibility of adding a comment to a JSON file?

JSON does not accept comments because of its structure. However, comments can be stored in a Key or data object. Ensure that your programme ignores the specified data element while processing the JSON.

28. What are some of the most extensively used JSON libraries in.NET?

In.net, there are several popular JSON libraries. Here are a few examples:

  • Newtonsoft: It is one of the most extensively used c# conversion frameworks. It is well-known for its versatility and performance. It also allows you to convert JSON to XML.
  • DataContractJsonSerializer: This is Microsoft's built-in library for dealing with JSON objects in the.net environment.

29. What are JSONP's limitations?

JSONP is used to get around web browsers' same-origin policies. It may be the ideal approach to get around the restriction, but it comes with drawbacks. They are as follows:

  • Because all JSONP calls must include a <script> element, the request can only be made via the GET method.
  • POST and PUT requests are not supported.
  • It can only be used for read-only APIs and services.    

30. What is JSON Schema, and how does it work?

JSON Schema is a specification for specifying JSON data structure in a JSON-based format.

31. In JavaScript, what exactly is JSON?

Because JSON is derived from the JavaScript programming language, it makes sense to utilise it as a data format in JavaScript. JavaScript Object Notation is abbreviated as JSON.

32. What are the benefits of using JSON?

  • It's utilised in developing JavaScript-based applications, such as browser extensions and webpages.
  • JSON is a serialisation and transmission standard for structured data over a network connection.
  • It's mainly used to send data from a server to web apps.
  • Web services and APIs use the JSON format to give public data.
  • It's compatible with today's programming languages.

33. Why is JSON used in Android?

  • It's a stand-alone data exchange format that's the most acceptable replacement for XML.
  • To manipulate JSON data, Android supports four distinct classes. 
Want to Know More About Android Concepts, Visit Android Tutorial.

34. What is the purpose of using JSON in Python?

JSON items are encoded and decoded using the Python programming language. The Python encode() function converts a Python object into a JSON string. The decode() function converts a JSON string to a Python object.

35. Why is JSON used in PHP?

The JSON decode function transforms a JSON encoded string into a PHP variable. Built-in JSON methods are available in PHP frameworks like Symfony and Laravel.

36. What is JSON Formatter, and how does it work?

The JSON Formatter & Validator aids in debugging JSON data by formatting and validating it so that it can be read easily by humans.

37. What is a JSON Viewer?

JSON Viewer — Converts  JSON Strings into an Easy-to-Read Format.

38. What is the purpose of a JSON Validator?

The JSON Validator aids in the debugging of JSON data by formatting and verifying it so that humans can read it.

39. What is the difference between Serialisation and Deserialisation in JSON?

JSON is a format for encoding objects that is based on strings. Serialisation transforms an object into a string, while deserialisation converts a string back into an object. When data is transferred or stored in a file, it must be in byte strings, although sophisticated objects are rare in this format. 

40. What exactly is a JSON String?

A string comprising zero or more Unicode characters wrapped in double-quotes is paraded by backslashes. A single character string represents a character. In C or Java, a string is similar to a string.

  • A string (U+0022) is a collection of Unicode code points enclosed in quotation marks. Except for the code points that must be escaped: quotation mark (U+0022), Reverse Solidus (U+005C), and the control characters U+0000 to U+001F, all code points may be inserted within quotation marks. Some characters have two-character escape sequence representations.
  • The quote mark character (U+0022) is represented by ", and the Reverse Solidus character (U+005C) is represented by \.
  • The Solidus character (U+002F) is represented by /.
  • The Backspace character (U+0008) is represented by the letter b.
  • The letter f represents the Form Feed character (U+000C).
  • The Line Feed character (U+000A) is represented by n.
  • The letter r represents the Carriage Return character (U+000D).
  • The letter t represents the Tabulation character (U+0009).


Having an idea of the questions that you can expect in the JSON interview will help you prepare well and perform better. So, keep all these JSON interview questions in mind, use them to improve your skills and prepare well.

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Last updated: 04 Jan 2024
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As a Senior Writer for Mindmajix, Saikumar has a great understanding of today’s data-driven environment, which includes key aspects such as Business Intelligence and data management. He manages the task of creating great content in the areas of Programming, Microsoft Power BI, Tableau, Oracle BI, Cognos, and Alteryx. Connect with him on LinkedIn and Twitter.

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