JSON body in Postman - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a JSON body in API testing?

A JSON body is the data sent in the request payload formatted as JSON. It tells the server what information the client wants to send or update.

beginner

Why do we use JSON format for request bodies in Postman?

JSON is easy to read and write, lightweight, and widely supported by APIs. It helps structure data clearly for communication between client and server.

beginner

How do you set a JSON body in Postman?

In Postman, select the 'Body' tab, choose 'raw', then select 'JSON' from the dropdown. Then type or paste your JSON data.

intermediate

What happens if your JSON body is not valid?

The server may reject the request with an error, or the API may not work as expected. Postman also shows an error if JSON syntax is incorrect.

beginner

Give an example of a simple JSON body for creating a user with name and email.

{ "name": "Alice", "email": "[e-mail]" }

What format should the request body be in when sending JSON data in Postman?

A raw with JSON selected

B form-data

C x-www-form-urlencoded

D binary

To send JSON data, you must select 'raw' and then choose 'JSON' so Postman sends the data correctly.

Which of these is a valid JSON body?

A <name>Bob</name>

B {name: 'Bob', age: 30}

C {"name": "Bob", "age": 30}

D name=Bob&age=30

Valid JSON requires double quotes around keys and string values, like in option A.

What error might you get if your JSON body is missing a closing brace?

A 401 Unauthorized

B SyntaxError or parsing error

C 404 Not Found

D Timeout error

Missing braces cause syntax errors because the JSON is not well-formed.

In Postman, where do you enter the JSON body for a POST request?

A Body tab

B Headers tab

C Params tab

D Authorization tab

The Body tab is where you input the data you want to send in the request.

Why is JSON preferred over XML for API request bodies?

A JSON is heavier and slower

B JSON requires special software to read

C XML is not supported by APIs

D JSON is easier to read and write

JSON is lightweight and easier for humans and machines to read and write compared to XML.

Explain how to create and send a JSON body in Postman for an API request.

Think about the steps in Postman interface to send JSON data.

Describe common errors that can happen with JSON bodies and how to avoid them.

Consider what makes JSON invalid and how Postman helps.