Top 30 JSON Interview Questions and Answers in 2023

Top 30 JSON Interview Questions And Answers

Are you preparing for a JSON interview? We have done the legwork for you. Below are the JSON questions that interviewers often ask when looking for the right candidate. To make your preparation hassle-free, we have included a sample answer for each interview question.

1. What Is The Meaning Of Json?

JSON is the abbreviation for JavaScript Object Notation. JSON is a lightweight, text-based data transition format. It is one of the simplest and most popular formats for data transition. The fact that it is a text-based format makes it easier for users to read and write it. Because of its lightweight property, a machine can generate or deconstruct it with ease. JSON is commonly used for the transmission and serialization of data between network connections.

2. Why Is Douglas Crockford Referred To As The Father Of Json?

Douglas Crockford is the person who discovered JSON. He is credited for first computing this text-based format back in 2000. It is for these reasons that he is known as the father of JSON.

3. What File Extension Is Used With Json?

The extension used with a JSON file is “.json” So if there is a JSON file called Example, it will have a .json extension such that it will read – Example.json. Since the file is text-based, it can be edited or viewed using notepad or another text editor.

4. What Is Json Used For?

JSON has many uses. Web services and APIs use it to transfer and format data. It is used for reading data from web servers as well as displaying data on a web page. It is used to transmit serialized data between systems over a network. JSON is also used together with many modern programming languages as well as JavaScript applications including websites and browser plugins.

5. Is Json Supported By All Programming Languages And Platforms?

Since JSON is a text-based file, almost all programming languages and platforms support it. Most technologies that are used to transmit data between different systems support this text-based file. In other words, programming languages such as PHP, Python, Java, Perl, C#, C++, and C all support JSON.

6. What Are The Advantages Of Json?

JSON offers several advantages over other formats used in data transmission and exchange. JSON is fast in nature and easy to use. Its syntax provides faster implementation and easier data parsing. Since JSON comes with a lightweight structure, it responds at a faster rate than other data exchange formats. Another advantage is that JSON is compatible with various browsers and operating systems. This compatibility makes it possible to easily attune JSON schema to different platforms. JSON also offers the advantage of supporting several data types such as Boolean, String, and integers.

7. State Some Limitations Associated With Json

JSON comes with its own share of setbacks. The most basic is that it does not support comments. The simple and lightweight properties of a JSON file render it unsuitable for handling large and complex data. As data in a JSON file becomes complex with hierarchical and nested structures, it becomes more difficult for humans to read it. Another limitation is that JSON does not support multimedia formats like images or rich text files.

8. What Are The Rules Associated With Json Syntax?

There are a number of rules that describe JSON structure. One of them is that data within a JSON file should be arranged in key-value pairs. Both the value and the key are divided by a colon with data on the right-side representing value and the left side representing the key. Square brackets “[ ]” are used within a JSON object to define arrays. The JSON objects are defined using curly braces. The left curly brace means the beginning of an object while the right curly brace signifies the end of the object. In addition, a comma is used when separating a pair of key-value from another pair.

9. What Similarities Exist Between Xml And Json?

JSON and XML share some similarities. Both play the function of transferring data between different systems. They feature a simple structure and they can also be read by humans. JSON and XML are both independent of programming language and they support hierarchical or nested structures. The structure of both XML and JSON supports Unicode. In addition, it is easy to parse JSON and XML easily through different programming languages.

10. Explain The Libraries That Are Widely Used In .Net For Json

Although several libraries are available in .net for JSON, Newtonsoft is one of the most commonly used frameworks. This library, which is widely used to convert using C#, is popular because of its performance and flexibility. Newtonsoft also supports conversions from JSON to XML. Another widely used framework is DataContractJsonSerializer, which is a built-in library. Microsoft provides this library within the .net environment to facilitate the handling of JSON objects.

11. Explain What You Understand By Jsonp

JSON with Padding or simply JSONP is a communication method that JavaScript programs utilize to call data that is present in a domain. It helps users to share data across systems without cross-domain restrictions. Besides, JSONP facilitates the sharing of data while evading the same-origin policy of browsers that prevents the running JavaScript code from reading data or elements fetched outside the originating site of a page.

12. What Are The Setbacks Of Jsonp?

While JSONP is a great technique that helps to build mashups, it doesn’t cater to all the needs of cross-domain communication. There isn’t any error handling for JSON with Padding calls. If dynamic script insertion functions, one gets called; otherwise, nothing happens at all. Another drawback is that using this technique may turn out to be risky when untrusted services are involved. JSONP exposes the hosting Web application to several attacks because a response returned by a JSONP service is simply wrapped in a function call. Also, JSONP cannot be applied for PUT or POST requests.

13. Why Would You Recommend Json Over Xml?

Compared to XML, JSON is lighter and faster. It supports several data types such as String, Boolean, Array, Number, Object, and Null. This is unlike XML only supports string data format. JSON objects are typed but XML data is typeless. Also, fetching values with JSON is as easy as reading from object property in a JavaScript code.

14. What Is Serialization In JSON?

Serialization is the process through which an object is converted into a string. When data is being stored in a file or transmitted, it is needed to be in form of byte strings. However, in this kind of data format, complex objects are seldom. Thus, serialization helps to transform these complex objects into byte strings. Once the byte strings have been transmitted, the receiver needs to recover the original objects from the received byte strings. 

15. Why Is Serialization Necessary?

Serialization is important particularly to customers because if objects are not serialized into JSON, they will not be in a format that can be understood by customers. Thus serializing objects into JSON helps to transform messages into a form that is understandable or makes sense to the system that sends the request.

16. State The Benefits Of Using Hierarchy In Json Classes

Using hierarchy in JSON-related classes makes it easy to add new class types in the future without interfering with the existing ones. A hierarchy offers more object-oriented implementation. With a hierarchy, it is easy to declare different kinds of objects in one JSON list provided they share the same Java superclass. Hierarchy in JSON supports automatic REST input validation when working with the Spring framework. One does not have to declare checking logic using complicated conditions and mixed fields.

17. Explain The Use Of The Hasownproperty() Method In Javascript

In JavaScript, the HasOwnProperty() method is used when checking if an object has a particular property. In other words, it helps to assess if an object has its own property or it has an inherited one. This method returns true when a property that is direct to an object is identified, even when the value is undefined or null. Otherwise, the HasOwnProperty() method returns false when a property is inherited or hasn’t been declared. Since most objects in JavaScript descend from objects, this technique can be called on a majority of JavaScript objects.

18. Briefly Tell Us What You Understand By $Ref In JSON Schema

A $ref is a pointer to a JSON schema. It also means a property or type in a schema. In JSON, a pointer assumes the form of A#B. “A” represents the relative path, that is, from the current schema to the targeted schema. On the other hand, “B” represents the whole path, starting from the schema’s root to property or type in the schema. If A is empty, it means an in-schema reference, which shows a property or type in the same schema. Otherwise, there is a cross-schema reference that signifies a reference to a different schema. When B is empty or # is not included, this indicates a reference to the whole schema.

19. What Do You Understand By A Dialect In Json Schema?

A dialect is a version of JSON schema and it represents a set of semantics and keywords that are used in the process of evaluating a schema. Every release of a JSON schema represents a new JSON schema dialect. Schemas help to declare the dialect that a schema conforms to. They also offer ways to describe custom dialects.

20. What Isthe Meaning Of $Schema In JSON?

In JSON, a $schema keyword is normally used when declaring the dialect of JSON Schema in which a schema was written. A $schema keyword value is used as the identifier for a schema and it can be used to validate whether a schema is valid or not based on the dialect that is identified by $schema. The schema that is used to describe another schema is referred to as meta-schema. A $schema is applied at the root level and applies to an entire document. It does not apply to documents that are referenced externally.

21. Explain The Meaning Of Json Array?

An array is basically a collection of values that are ordered systematically. A JSON array consists of a pair of square bracket tokens that surround values. An array starts with a left square bracket and ends with a right square bracket. Values within an array are separated using a comma. In a JSON syntax, there is no specific meaning to value order that is defined. But JSON array structure is used often when certain semantics to ordering exists. 

22. What Do You Understand By Yaml?

YAML is a human-readable and lightweight data-representation language that presents data in a format that is easy to read even with complex features. YAML is a superset of JSON and thus it can be used to parse JSON using a YAML parser. YAML specifications permit explicit data typing as well as user-defined data types. The data types that are commonly used in YAML are numbers, Boolean, sequences, nested values, null values, dates and timestamps, and strings.

23. Tell Us Some Differences Between Json And Yaml

While comments are not permitted in JSON, they are used in YAML and are denoted using a number or hash sign. Arrays and objects in JSON are denoted in brackets and braces. On the other hand, double-space characters are used to denote hierarchy in YAML. When using strings in JSON, they must be placed in double quotes. But string quotes are optional in YAML, although the latter supports both double and single quotes. In JSON, root nodes should be used either as an object or array but in YAML, they can be any of the supported data types.

24. What Is NIEM?

NIEM is a data model and is the abbreviation for National Information Exchange Model. This model helps to create automated enterprise-wide information exchanges that can be developed uniformly, maintained centrally, identified quickly, and reused efficiently. NIEM facilitates information sharing as well as helps to focus on information exchanged by organizations as part of their intended or current business practices. It also helps to provide tools, standardize content and manage data exchange processes.

25. What Is JSON-RPC?

JSON-RPC refers to a simple remote procedure call protocol, which shares similarities with XML-RPC. This protocol employs a lightweight JSON format rather than XML. JSON-RPC permits notifications regarding data that is forwarded to the server that doesn’t need a response. It also enables sending of multiple calls to a server that can be answered asynchronously.

26. Why Is Stringify Necessary In JSON?

Stringify() method is used in JavaScript to create a JSON string. When JSON developers are creating applications using JavaScript, they often serialize data into strings before storing it into databases. They also serialize data in order to send it to a web server or an API. To do this, data has to be in strings form. Thus, the JSON.stringify () method is used to convert data into strings before storing or sending it.  

27. What Is Meant By A Json Schema?

A JSON schema offers a JSON vocabulary for validating as well as defining JSON instances. Each JSON schema contains one or multiple key-value keywords or pairs. Schemas may include keywords that contain a description keyword that provides a definition for the property or data type. They may also include a $ref keyword that helps to provide a JSON pointer to a different schema, property, or type. Schemas can also contain an $id keyword that provides a base URL that is used to reference the schema, property, or data type.

28. Explain What You Understand By Bson

BSON means Binary JSON and is a format for computer data interchange. It is a form of binary that is used to represent complex or simple data structures such as integer indexed arrays and associative arrays. BSON is often used to store documents in collections. It provides additional support for data types such as binary and Date that are not supported by JSON.

29. As A Json Developer, How Do You Stay Motivated?

I read a lot about the news and developments happening in the JSON area. In doing so, I learn how other developers are addressing common challenges in the area. I also get to learn the methods they have applied and achieved success. This knowledge motivates me to press on and overcome related challenges. I also participate in local seminars and workshops that relate to the industry. This participation offers me the opportunity to meet other developers and learn what they are doing differently.

30. Where Do You See Yourself In Five Years

I anticipate that I will have gained significant knowledge in the field of JSON. I will be able to handle more challenges than I can today. I will also be able to effectively handle more complex tasks as well as managerial roles. I also intend to enroll in a JSON-related course in order to enhance my skills and knowledge.


By studying and rehearsing these JSON questions and answers, you will significantly enrich your knowledge and maximize your chances of getting hired. Be sure to customize them to your specific situation, experience, and qualification. Also, dress decently and arrive early for the interview.