How to Parse JSON Response in Postman: Simple Guide

In Postman, you can parse a JSON response by using pm.response.json() in the Tests tab. This method converts the response body into a JavaScript object, allowing you to access values with dot notation or bracket notation.

Syntax

Use pm.response.json() to convert the JSON response body into a JavaScript object. Then access properties using dot notation or bracket notation.

• pm.response.json(): Parses the response body as JSON.
• jsonData.property: Access a property from the parsed JSON.

javascript

const jsonData = pm.response.json();
const value = jsonData.key; // Access value by key

Example

This example shows how to parse a JSON response and check if a specific value matches the expected result using an assertion.

javascript

pm.test("Status code is 200", () => {
    pm.response.to.have.status(200);
});

const jsonData = pm.response.json();
pm.test("User name is correct", () => {
    pm.expect(jsonData.user.name).to.eql("John Doe");
});

Output

Test Results:
✔ Status code is 200
✔ User name is correct

Common Pitfalls

Common mistakes when parsing JSON in Postman include:

• Trying to parse a response that is not JSON, causing errors.
• Accessing properties that do not exist, leading to undefined values.
• Not waiting for the response before parsing.

Always check the response content type and use safe property access.

javascript

/* Wrong way: Parsing non-JSON response */
// const jsonData = pm.response.json(); // This will throw error if response is not JSON

/* Right way: Check content type before parsing */
if (pm.response.headers.get('Content-Type').includes('application/json')) {
    const jsonData = pm.response.json();
    // safe to access jsonData properties
}

Quick Reference

Action	Code Snippet	Description
Parse JSON response	const jsonData = pm.response.json();	Convert response body to JavaScript object
Access property	jsonData.key	Get value of 'key' from JSON object
Assert value	pm.expect(jsonData.key).to.eql('value');	Check if value matches expected
Check content type	pm.response.headers.get('Content-Type')	Verify response is JSON before parsing

Key Takeaways

Use pm.response.json() to parse JSON response into a JavaScript object.

Always verify the response content type is JSON before parsing.

Access JSON properties safely to avoid undefined errors.

Use pm.expect() assertions to validate parsed data in tests.

Parsing JSON in Postman helps automate API response validation easily.