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 of the following is an example of a valid JSON number?

A) Both B and C

B) 123.45

C) 123

D) "123"

2 / 30

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

A) To manage subscriptions

B) To format query results

C) To handle authentication

D) To define the schema

3 / 30

3. What is used to enclose JSON keys?

A) Double quotes

B) Parentheses

C) Single quotes

D) No quotes

4 / 30

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

A) Defines the maximum number of keys in an object

B) Defines the keys allowed in an object

C) Lists all required fields in an object

D) Specifies the data type of an array

5 / 30

5. 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

6 / 30

6. How do you handle very large JSON data efficiently in JavaScript?

A) Split the JSON file into multiple smaller files

B) Both B and C

C) Load the entire JSON object in memory

D) Use streaming parsers like JSONStream

7 / 30

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

A) String

B) All of the above

C) Float

D) Object

8 / 30

8. Which HTTP header is critical for securing JSON responses?

A) X-Content-Type-Options

B) Access-Control-Allow-Origin

C) Accept-Encoding

D) Content-Type

9 / 30

9. Which of the following is a valid JSON string?

A) Hello

B) "Hello"

C) “Hello”

D) 'Hello'

10 / 30

10. What is the correct syntax for a JSON object?

A) {key = "value"}

B) [key: "value"]

C) {"key": "value"}

D) {key: "value"}

11 / 30

11. Which of the following is NOT a valid JSON key?

A) "name!"

B) "_name"

C) "123name"

D) name

12 / 30

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

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

B) Use JSON.prettyPrint()

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

D) Add a spaces property to the JSON object

13 / 30

13. What will JSON.stringify({ key: undefined }) return?

A) {"key": null}

B) {}

C) Throws an error

D) {"key": "undefined"}

14 / 30

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

A) They must be enclosed in double quotes

B) They support both integers and floats

C) They must include a decimal point

D) They cannot be negative

15 / 30

15. How are multiple key-value pairs separated in a JSON object?

A) Dot

B) Hyphen

C) Semicolon

D) Comma

16 / 30

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

A) Use a linter or formatter tool

B) Use the browser's developer tools

C) All of the above

D) Log errors in the console

17 / 30

17. How do you deep clone a JSON-compatible object in JavaScript?

A) Use JSON.clone()

B) Use the clone() method

C) Use Object.assign()

D) Use JSON.stringify() and JSON.parse()

18 / 30

18. What does the JSON.parse() method do in JavaScript?

A) Converts a JSON string into a JavaScript object

B) Validates a JSON string

C) Parses a JSON string into an XML object

D) Converts a JavaScript object into a JSON string

19 / 30

19. What is the result of running JSON.parse('{"key":value}') in JavaScript?

A) null

B) SyntaxError: Unexpected identifier

C) ReferenceError

D) A key-value pair object

20 / 30

20. What data type is represented by {} in JSON?

A) Null

B) String

C) Object

D) Array

21 / 30

21. Which HTTP method is commonly used to fetch JSON data from an API?

A) DELETE

B) POST

C) GET

D) PUT

22 / 30

22. Which of these is NOT a valid JSON value?

A) A boolean

B) A string

C) A function

D) A null value

23 / 30

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

A) Using the error property of the response

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

C) Using fetchError() function

D) Errors cannot be handled in fetch()

24 / 30

24. What does JSON stand for?

A) JavaScript Online Network

B) JavaScript Object Notation

C) Java Syntax Object Notation

D) Java Online Syntax Network

25 / 30

25. How can you validate JSON in a secure and efficient way?

A) Use custom regular expressions

B) Manually check the JSON

C) Ignore validation for trusted sources

D) Use a JSON Schema validator

26 / 30

26. How can you identify unused keys in a JSON object?

A) JSONLint

B) Postman

C) JSON Formatter

D) Static analysis tools or manual comparison

27 / 30

27. What does a JSON array of objects look like?

A) { "array": [ "value1", "value2" ] }

B) [ { "key": "value" }, { "key": "value" } ]

C) { "object1": "value1", "object2": "value2" }

D) [ "object1", "object2" ]

28 / 30

28. What is the correct JSON format for a boolean value?

A) True or False

B) "true" or "false"

C) true or false

D) TRUE or FALSE

29 / 30

29. What does the Accept header specify in an API request?

A) The client type

B) The data format expected in the response

C) The authentication type

D) The server's API version

30 / 30

30. Which tool can convert a JSON file into a different format like CSV?

A) Postman

B) jq

C) JSONLint

D) JSON Formatter

Your score is

The average score is 40%

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)

Online Quiz Test (with time limit)

10 Minutes SQL Quiz Test Online

HTML Quiz Test Online

SQL Quiz Test Online (30 random Questions)

Related