JSON Quiz Test Online (30 random Questions) 2026

This quick 30-minute challenge consists of 30 random multiple-choice questions designed to test your knowledge across various JSON topics, including the introduction to JSON, JSON syntax and basics, data types, operations in JavaScript, APIs and JSON, advanced structures, JSON Schema, tools and debugging, as well as performance and security considerations. Whether you’re new to JSON or looking to refine your skills, this quiz will enhance your understanding of JSON’s role in modern web development.

0 votes, 0 avg

You have 30 minutes to complete the quiz. The timer will start when you click the 'Start Quiz' button. Please ensure you are ready before beginning.

Time is up! Your quiz has ended. Your responses have been submitted automatically.

30 Minutes JSON Quiz Test Online

Welcome to the JSON Quiz! This quick 30-minute challenge consists of 30 random multiple-choice questions designed to test your knowledge across various JSON topics, including the introduction to JSON, JSON syntax and basics, data types, operations in JavaScript, APIs and JSON, advanced structures, JSON Schema, tools and debugging, as well as performance and security considerations. Whether you're new to JSON or looking to refine your skills, this quiz will enhance your understanding of JSON's role in modern web development.

1 / 30

1. What type of data does a JSON object contain?

A) Key-value pairs

B) Only numbers

C) Only text

D) Only arrays

2 / 30

2. What is the best approach to log sensitive information within JSON responses?

A) Log the raw JSON data as is

B) Use a secure logging framework and mask sensitive data

C) Use JSON.stringify()

D) Avoid logging altogether

3 / 30

3. Which of the following is NOT a supported data type in JSON?

A) Number

B) Undefined

C) Boolean

D) String

4 / 30

4. What does a JSON path debugger do?

A) Converts JSON to CSV

B) Validates JSON syntax

C) Extracts specific values from JSON

D) Beautifies JSON

5 / 30

5. What is the purpose of JSON in REST APIs?

A) To render HTML pages

B) To structure and exchange data between client and server

C) To validate API responses

D) To define API endpoints

6 / 30

6. What is the purpose of the dependencies keyword in JSON Schema?

A) To define type constraints

B) To define key dependencies

C) To validate nested objects

D) To specify default values

7 / 30

7. Which of the following values is not valid in JSON?

A) 123

B) undefined

C) "Hello"

D) null

8 / 30

8. What is JSON primarily used for?

A) Sending emails

B) Creating animations

C) Styling web pages

D) Data exchange between a client and a server

9 / 30

9. What is the maximum depth for nesting in JSON?

A) 10 levels

B) Unlimited

C) 5 levels

D) Depends on the programming language and environment

10 / 30

10. How do you validate that a JSON object has no additional fields?

A) maxProperties: 0

B) additionalProperties: false

C) properties: []

D) additionalFields: false

11 / 30

11. Why is it important to remove unused fields from JSON responses?

A) To prevent JSON schema validation errors

B) To avoid key duplication

C) To reduce payload size and improve performance

D) To enhance JSON readability

12 / 30

12. How does JSON.stringify() handle functions in objects?

A) Adds null in place of functions

B) Functions are ignored

C) Throws an error

D) Functions are converted to strings

13 / 30

13. Which JSON data type is used to group key-value pairs?

A) Number

B) Object

C) String

D) Array

14 / 30

14. What does the title keyword do in JSON Schema?

A) Gives a short label to the schema or property

B) Provides a description of the schema

C) Sets a required field

D) Specifies a string pattern

15 / 30

15. What is a common vulnerability associated with parsing untrusted JSON?

A) JSON Injection

B) JSON Flooding

C) JSON Brute Force

D) JSON Parsing Loops

16 / 30

16. JSON is a strict subset of which language?

A) JavaScript

B) SQL

C) Python

D) XML

17 / 30

17. Which of the following formats can JSON be easily converted into for data visualization?

A) All of the above

B) CSV

C) HTML

D) XML

18 / 30

18. Which tool can be used to measure JSON parsing performance in JavaScript?

A) Chrome DevTools

B) JSON Formatter

C) JSON Schema Validator

D) JSONLint

19 / 30

19. How do you handle errors in a fetch() request?

A) Using try...catch blocks or then().catch() methods

B) Errors cannot be handled in fetch()

C) Using fetchError() function

D) Using the error property of the response

20 / 30

20. What happens when you pass a replacer function to JSON.stringify()?

A) Throws an error if the function is invalid

B) It filters the properties to be included in the JSON string

C) It ensures all properties are stringified

D) It validates the JSON string

21 / 30

21. Which HTTP method is typically used for sending data to an API?

A) OPTIONS

B) GET

C) POST

D) DELETE

22 / 30

22. How are floating-point numbers represented in JSON?

A) "1.23"

B) 1.23f

C) float(1.23)

D) 1.23

23 / 30

23. How do you identify invalid JSON in a web application?

A) Use a linter or formatter tool

B) Log errors in the console

C) Use the browser's developer tools

D) All of the above

24 / 30

24. What does a JSON Formatter do?

A) Parses JSON into JavaScript objects

B) Formats JSON into a readable and indented structure

C) Compresses JSON into a single line

D) Converts JSON to XML

25 / 30

25. What is the root element of a JSON document?

A) A number

B) An object or array

C) A string

D) A key-value pair

26 / 30

26. What does the oneOf keyword do in JSON Schema?

A) Combines multiple schemas

B) Ensures that the data matches exactly one of the specified schemas

C) Validates against one specific type

D) Requires all listed schemas to match

27 / 30

27. What is the primary role of JSON in GraphQL APIs?

A) To define the schema

B) To format query results

C) To manage subscriptions

D) To handle authentication

28 / 30

28. How is JSON used in data interchange for machine learning models?

A) To render visualizations

B) To train models directly

C) To serialize model configurations and results

D) To compile machine learning libraries

29 / 30

29. How is null represented in JSON?

A) null

B) (null)

C) "null"

D) NULL

30 / 30

30. How can large nested JSON objects impact performance?

A) They slow down parsing and increase memory usage

B) They improve network speed

C) They reduce API latency

D) They make JSON more secure

Your score is

The average score is 39%

Rate Your Experience!

Anonymous feedback

Thank you for your feedback! We appreciate your input.

Docker Quiz Test Online (30 random Questions)

MongoDB Quiz Test Online (30 random Questions)

Bootstrap Quiz Test Online (30 random Questions)

10 Minutes SQL Quiz Test Online

10 Minutes Bootstrap Quiz Test Online

10 Minutes JSON Quiz Test Online

Related