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. Which method can be used to transform a JSON object into an iterable array?

A) Object.keys()

B) Object.values()

C) All of the above

D) Object.entries()

2 / 30

2. What does the properties keyword do in JSON Schema?

A) Specifies the data type of an array

B) Defines the maximum number of keys in an object

C) Lists all required fields in an object

D) Defines the keys allowed in an object

3 / 30

3. How do you reference the parent key in a deeply nested JSON object?

A) Use a library to navigate JSON paths

B) JSON does not support parent references

C) Use key.parent

D) Use parent() function

4 / 30

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

A) To compile machine learning libraries

B) To train models directly

C) To render visualizations

D) To serialize model configurations and results

5 / 30

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

A) To specify default values

B) To define key dependencies

C) To define type constraints

D) To validate nested objects

6 / 30

6. What is the output of JSON.stringify([1, undefined, 2])?

A) "[1, undefined, 2]"

B) "[1, null, 2]"

C) Throws a TypeError

D) "[1, , 2]"

7 / 30

7. What symbol is used to enclose a JSON array?

A) ()

B) {}

C) <>

D) []

8 / 30

8. Which of the following is true about JSON numbers?

A) They must be enclosed in double quotes

B) They cannot be negative

C) They must include a decimal point

D) They support both integers and floats

9 / 30

9. How does Firebase use JSON?

A) To define cloud functions

B) For real-time database storage and synchronization

C) To manage authentication tokens

D) To render user interfaces

10 / 30

10. What is the difference between allOf and oneOf in JSON Schema?

A) allOf validates all schemas, oneOf validates only one schema

B) allOf allows duplicates, oneOf does not

C) allOf is for strings, oneOf is for arrays

D) oneOf requires at least one match, allOf requires none

11 / 30

11. How does Postman help in debugging JSON APIs?

A) It beautifies JSON data

B) It converts JSON to XML

C) It validates JSON against schemas

D) It sends requests and shows JSON responses

12 / 30

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

A) null

B) 123

C) "Hello"

D) undefined

13 / 30

13. What is a safe alternative to eval() for parsing JSON in JavaScript?

A) JSON.parse()

B) JSON.stringify()

C) JSON.minify()

D) JSON.debug()

14 / 30

14. Which of these is a valid JSON array of strings?

A) [apple, banana, cherry]

B) ["apple", "banana", "cherry"]

C) ["apple", 'banana', "cherry"]

D) ['apple', 'banana', 'cherry']

15 / 30

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

A) Functions are converted to strings

B) Throws an error

C) Adds null in place of functions

D) Functions are ignored

16 / 30

16. Which of the following JSON strings can be parsed without error?

A) '{name: "John", age: 30}'

B) '{name: John, age: 30}'

C) '{"name": "John", "age": 30}'

D) '{"name": John, "age": 30}'

17 / 30

17. Which of the following is the correct JSON format for a key-value pair?

A) {"key": value}

B) {key: value}

C) {key = value}

D) {"key": "value"}

18 / 30

18. What happens if a key in a JSON object contains special characters?

A) The key is ignored

B) The key must be enclosed in double quotes

C) It throws an error

D) The special characters are escaped automatically

19 / 30

19. Can a JSON object have duplicate keys?

A) Only in nested objects

B) Only in arrays

C) Yes

D) No

20 / 30

20. Which of the following is a commonly used library for making API requests in JavaScript?

A) D3.js

B) jQuery

C) Axios

D) Lodash

21 / 30

21. What does a 404 status code signify in an API response?

A) Bad request

B) Unauthorized access

C) Resource not found

D) Internal server error

22 / 30

22. What happens when you use JSON.parse() on an invalid JSON string?

A) Skips invalid parts

B) Throws a SyntaxError

C) Returns null

D) Converts to an empty object

23 / 30

23. Which of the following is NOT a JSON data type?

A) Null

B) String

C) Boolean

D) Date

24 / 30

24. What will be the output of the code: JSON.stringify({ key1: "value1", key2: function() { return "value2"; } });

A) {"key1": "value1", "key2": "value2"}

B) Throws an error

C) {"key1": "value1", "key2": null}

D) {"key1": "value1"}

25 / 30

25. What is the use of the $ref keyword in JSON Schema?

A) To specify required properties

B) To include reusable schema definitions

C) To define a default value

D) To reference external files

26 / 30

26. How do you access the second element of a JSON array ["apple", "banana", "cherry"]?

A) array.index(1)

B) array[1]

C) array["banana"]

D) array.get(1)

27 / 30

27. How can you format JSON output with spaces using JSON.stringify()?

A) Use JSON.prettyPrint()

B) Add a spaces property to the JSON object

C) Use the JSON.stringify(obj, null, 4) method

D) Pass a null parameter to JSON.stringify()

28 / 30

28. Which of the following JSON data types is valid?

A) Float

B) Object

C) All of the above

D) String

29 / 30

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

A) JSON Parsing Loops

B) JSON Injection

C) JSON Brute Force

D) JSON Flooding

30 / 30

30. What does the .eslintrc.json file configure in JavaScript projects?

A) Project dependencies

B) Linting rules and code quality settings

C) Server configurations

D) Database schemas

Your score is

The average score is 41%

Rate Your Experience!

Anonymous feedback

Thank you for your feedback! We appreciate your input.

10 Minutes Docker Quiz Test Online

Bootstrap Quiz Test Online (30 random Questions)

SQL Quiz Test Online (30 random Questions)

10 Minutes Bootstrap Quiz Test Online

10 Minutes HTML Quiz Test Online

HTML Quiz Test Online

Related