This is the response from Postman:

    "data": [
            "firstname": "tahaq",
            "lastname": "postmanq",
            "accountenabled": "true",
            "email": "tahaiq@hotmail.com",
            "phoneactive": true,
            "phonenumber": "+18738021112",
            "brandname": "kwikset",
            "emailnotification": true,
            "smsnotification": true,
            "pushnotification": true
    "total": 1

Test in postman I am using:

let jsonData = JSON.parse(responseBody);
pm.test("Verify firstname", function () { 

Error return as:

Verify firstname | AssertionError: expected undefined to equal 'tahaq'

Just to add to the above answer , in JSON {} is a JSON object and [] is an Json array.

So the JSON.parse just parses the response string into proper JSON. As the response starts with a {} you can access elements inside it as key-value.

hence , jsonData.data will give content inside 'data' field. But now to access content inside data you have to use index as data is json array [].

And as there is only one json object {} in the array, use jsonData.data[0] means, the first JSON object in the jsonArray. Now again we have a jsonObject , so to get the field "firstname" we use:


When ever you are in doubt in postman just print the content using console.log.

so just print :

let jsonData = JSON.parse(responseBody);

The console output could be viewed in postman console which is under view> show postman console (or by pressing alt+ctrl+c) :

enter image description here

When you print it , you can JSON.parse prints the same response body :

enter image description here

so here we can see the structure like data>[0]>firstname:


The problem is with this: pm.expect(jsonData.firstname).

You left out data which is an array, so you need to write: pm.expect(jsonData.data[0].firstname) in order to find firstname in your json.


you have an array, so do this

let jsonData = JSON.parse(responseBody);
pm.test("Verify firstname", function () { 

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