JSON body in Postman - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a JSON body with a user's name.

Postman

{
  "name": "[1]"
}

Drag options to blanks, or click blank then click option'

Anull

BJohn Doe

Ctrue

D12345

Attempts:

3 left

💡 Hint

Common Mistakes

Using numbers or boolean values instead of a string for the name.

The JSON body requires a string value for the "name" key. "John Doe" is a valid string.

2fill in blank

medium

Complete the JSON body to include an age field with a number value.

Postman

{
  "age": [1]
}

Drag options to blanks, or click blank then click option'

A"twenty"

B"30"

C30

Dtrue

Attempts:

3 left

💡 Hint

Common Mistakes

Putting numbers inside quotes, making them strings.

Using boolean values instead of numbers.

The age field should be a number without quotes in JSON. 30 is a valid number.

3fill in blank

hard

Fix the error in the JSON body by completing the missing value for the "isActive" field.

Postman

{
  "isActive": [1]
}

Drag options to blanks, or click blank then click option'

A"true"

BFalse

C"false"

Dtrue

Attempts:

3 left

💡 Hint

Common Mistakes

Using capitalized True or False instead of lowercase true or false.

Putting boolean values inside quotes.

Boolean values in JSON are lowercase true or false without quotes. "true" is a string, which is incorrect.

4fill in blank

hard

Fill both blanks to create a JSON body with a list of hobbies.

Postman

{
  "hobbies": [[1], [2]]
}

Drag options to blanks, or click blank then click option'

A"reading"

B"swimming"

Creading

Dswimming

Attempts:

3 left

💡 Hint

Common Mistakes

Leaving out quotes around string elements in the array.

JSON array elements must be strings with quotes. "reading" and "swimming" are correct string values.

5fill in blank

hard

Fill all three blanks to create a JSON body with nested user info.

Postman

{
  "user": {
    "name": [1],
    "age": [2],
    "isMember": [3]
  }
}

Drag options to blanks, or click blank then click option'

A"Alice"

B28

Cfalse

D"28"

Attempts:

3 left

💡 Hint

Common Mistakes

Putting numbers or booleans inside quotes.

Using capitalized boolean values.

The name is a string with quotes, age is a number without quotes, and isMember is a boolean false without quotes.

Practice

1. What is the correct way to represent a JSON body with a user's name and age in Postman?

easy

A. {"name": "Alice", "age": 30}

B. {name: Alice, age: 30}

C. {'name': 'Alice', 'age': 30}

D. {name = "Alice", age = 30}

Solution

1. Step 1: Identify JSON syntax rules

   JSON keys and string values must be in double quotes. Numbers do not need quotes.

2. Step 2: Check each option for correct JSON format

   {"name": "Alice", "age": 30} uses double quotes correctly around keys and string values. The other options use incorrect quotes or syntax.

3. Final Answer:

   {"name": "Alice", "age": 30} -> Option A

4. Quick Check:

   JSON keys and strings use double quotes = A [OK]

Hint: Always use double quotes for keys and string values in JSON [OK]

Common Mistakes:

• Using single quotes instead of double quotes
• Omitting quotes around keys
• Using equal signs instead of colons

2. Which of the following is a valid JSON body to send a list of colors in Postman?

easy

A. {"colors": ("red", "green", "blue")}

B. {colors: [red, green, blue]}

C. {"colors": "red", "green", "blue"}

D. {"colors": ["red", "green", "blue"]}

Solution

1. Step 1: Understand JSON array syntax

   Arrays in JSON are enclosed in square brackets with comma-separated values, strings in double quotes.

2. Step 2: Validate each option's array format

   {"colors": ["red", "green", "blue"]} correctly uses square brackets and double quotes. The other options are invalid: one uses parentheses, another is missing array brackets, and one lacks quotes around strings and keys.

3. Final Answer:

   {"colors": ["red", "green", "blue"]} -> Option D

4. Quick Check:

   Arrays use square brackets and double quotes = B [OK]

Hint: Use square brackets for arrays and double quotes for strings [OK]

Common Mistakes:

• Using parentheses instead of square brackets
• Missing quotes around string values
• Omitting brackets for arrays

3. Given this JSON body sent in Postman:

{
  "user": {
    "id": 101,
    "active": true
  },
  "roles": ["admin", "editor"]
}

What is the value of user.active?

medium

A. null

B. true

C. false

D. "true"

Solution

1. Step 1: Locate the key user.active in the JSON

   Inside the "user" object, the key "active" has the value true without quotes, meaning boolean true.

2. Step 2: Understand JSON boolean values

   Boolean true is a literal, not a string. So the value is the boolean true, not the string "true".

3. Final Answer:

   true -> Option B

4. Quick Check:

   Boolean true is unquoted true = D [OK]

Hint: Booleans in JSON are unquoted true or false [OK]

Common Mistakes:

• Confusing boolean true with string "true"
• Assuming missing keys have null values
• Misreading nested object structure

4. You wrote this JSON body in Postman:

{
  "product": "Book",
  "price": 12.99,
  "inStock": yes
}

What is the error in this JSON body?

medium

A. "price" should be a string in quotes

B. "inStock" value should be true or false without quotes

C. "inStock" value 'yes' is invalid, should be true or false

D. Missing comma after "price" value

Solution

1. Step 1: Check the value of "inStock" key

   The value 'yes' is not a valid JSON boolean or string because it lacks quotes.

2. Step 2: Identify correct boolean values in JSON

   JSON booleans are true or false without quotes. Strings must be in double quotes. 'yes' without quotes is invalid.

3. Final Answer:

   "inStock" value 'yes' is invalid, should be true or false -> Option C

4. Quick Check:

   Boolean values must be true/false unquoted = C [OK]

Hint: Use true/false for booleans, not yes/no or strings [OK]

Common Mistakes:

• Using yes/no instead of true/false
• Not quoting string values
• Confusing number and string types

5. You want to send this JSON body in Postman to update a user's profile:

{
  "user": {
    "name": "Bob",
    "email": "[e-mail]",
    "preferences": {
      "notifications": false,
      "themes": ["dark", "blue"]
    }
  }
}

Which of the following changes will correctly add a new preference "language" set to "en" inside "preferences"?

hard

A. { "user": { "name": "Bob", "email": "[e-mail]", "preferences": { "notifications": false, "themes": ["dark", "blue"], "language": "en" } } }

B. { "user": { "name": "Bob", "email": "[e-mail]", "preferences": { "notifications": false, "themes": ["dark", "blue"] }, "language": "en" } }

C. { "user": { "name": "Bob", "email": "[e-mail]", "preferences": { "notifications": false, "themes": ["dark", "blue"] }, "preferences.language": "en" } }

D. { "user": { "name": "Bob", "email": "[e-mail]", "preferences": { "notifications": false, "themes": ["dark", "blue"] }, "preferences": { "language": "en" } } }

Solution

1. Step 1: Understand nested object update in JSON

   To add a new key inside "preferences", it must be inside the existing "preferences" object.

2. Step 2: Check each option's structure

   { "user": { "name": "Bob", "email": "[e-mail]", "preferences": { "notifications": false, "themes": ["dark", "blue"], "language": "en" } } } adds "language": "en" inside "preferences" correctly. { "user": { "name": "Bob", "email": "[e-mail]", "preferences": { "notifications": false, "themes": ["dark", "blue"] }, "language": "en" } } adds "language" outside "preferences". { "user": { "name": "Bob", "email": "[e-mail]", "preferences": { "notifications": false, "themes": ["dark", "blue"] }, "preferences.language": "en" } } uses invalid key "preferences.language". { "user": { "name": "Bob", "email": "[e-mail]", "preferences": { "notifications": false, "themes": ["dark", "blue"] }, "preferences": { "language": "en" } } } overwrites "preferences" object, losing existing keys.

3. Final Answer:

   { "user": { "name": "Bob", "email": "[e-mail]", "preferences": { "notifications": false, "themes": ["dark", "blue"], "language": "en" } } } -> Option A

4. Quick Check:

   Nested keys must be inside existing objects = A [OK]

Hint: Add new keys inside existing nested objects, not outside [OK]

Common Mistakes:

• Adding keys outside nested objects
• Using dot notation as key name
• Overwriting entire nested objects accidentally