Why Using extracted data in next request in Postman? - Purpose & Use Cases

The Big Idea

What if your tests could talk to each other and share data automatically, saving you hours of tedious work?

The Scenario

Imagine testing an online store API where you first create a user, then need to use that user's ID to add items to their cart. Doing this manually means copying the user ID from one response and pasting it into the next request every time.

The Problem

This manual copying is slow and easy to mess up. You might copy the wrong ID or forget to update it, causing tests to fail or give wrong results. It's like writing down a phone number on paper and then dialing it by hand every time--tedious and error-prone.

The Solution

Using extracted data in the next request automates this process. Postman can grab the needed data from one response and automatically insert it into the next request. This saves time, reduces mistakes, and makes your tests reliable and repeatable.

Before vs After

✗ Before

POST /createUser
// Copy userId from response
POST /addToCart
Body: {"userId": "copied_id_here", "item": "book"}

✓ After

POST /createUser
pm.environment.set('userId', pm.response.json().id);

POST /addToCart
Body: {"userId": "{{userId}}", "item": "book"}

What It Enables

This lets you build smooth, connected test flows that mimic real user actions without lifting a finger to copy data.

Real Life Example

For example, when testing a signup and login flow, you can create a user, extract their token, and use that token automatically in the login request to verify access--all in one automated run.

Key Takeaways

Manual copying of data between requests is slow and error-prone.

Extracting data automatically ensures accuracy and speed.

It enables building realistic, connected test scenarios easily.

Practice

1. What is the main purpose of extracting data from one Postman response to use in the next request?

easy

A. To speed up the test execution by skipping requests

B. To automatically generate random data for requests

C. To avoid writing tests for each request separately

D. To simulate real workflows where requests depend on each other

Solution

1. Step 1: Understand data dependency in workflows

   In real APIs, some requests need data from previous responses to work correctly.

2. Step 2: Recognize the role of data extraction

   Extracting data lets you pass dynamic values from one request to the next, simulating real user flows.

3. Final Answer:

   To simulate real workflows where requests depend on each other -> Option D

4. Quick Check:

   Data extraction = simulate dependent requests [OK]

Hint: Remember: Extract to reuse data in next request [OK]

Common Mistakes:

• Thinking extraction speeds up tests by skipping requests
• Believing extraction replaces writing tests
• Confusing extraction with random data generation

2. Which Postman code snippet correctly saves a value from a response JSON to an environment variable named userId?

easy

A. pm.variables.set('userId', pm.response.json().id);

B. pm.setEnvironment('userId', pm.response.json().id);

C. pm.environment.set('userId', pm.response.json().id);

D. pm.environment.save('userId', pm.response.json().id);

Solution

1. Step 1: Identify correct method to set environment variable

   The correct method is pm.environment.set to save a variable in environment scope.

2. Step 2: Check syntax correctness

   pm.environment.set('userId', pm.response.json().id); uses pm.environment.set('userId', pm.response.json().id); which is correct syntax and usage.

3. Final Answer:

   pm.environment.set('userId', pm.response.json().id); -> Option C

4. Quick Check:

   Use pm.environment.set() to save variables [OK]

Hint: Use pm.environment.set('var', value) to save data [OK]

Common Mistakes:

• Using pm.setEnvironment which does not exist
• Using pm.environment.save which is invalid
• Using pm.variables.set which sets local variables, not environment

3. Given this test script in Postman after a response:

pm.environment.set('token', pm.response.json().authToken);

And the next request uses the header:

Authorization: Bearer {{token}}

What will be the value of the Authorization header if the response JSON is {"authToken": "abc123"}?

medium

A. Authorization: Bearer {{token}}

B. Authorization: Bearer abc123

C. Authorization: Bearer pm.response.json().authToken

D. Authorization: Bearer

Solution

1. Step 1: Extract token from response JSON

   The script saves the value of authToken which is "abc123" into environment variable token.

2. Step 2: Use environment variable in next request header

   The header uses {{token}} which Postman replaces with the saved value "abc123".

3. Final Answer:

   Authorization: Bearer abc123 -> Option B

4. Quick Check:

   {{token}} replaced by saved value [OK]

Hint: Saved variables replace {{var}} placeholders automatically [OK]

Common Mistakes:

• Expecting {{token}} to remain as literal text
• Using wrong variable name causing empty header
• Confusing script syntax with header value

4. You wrote this test script to save a user ID:

pm.environment.set('userId', pm.response.json().user.id);

But the next request using {{userId}} fails with an empty value. What is the most likely cause?

medium

A. The JSON path is incorrect; user ID is at pm.response.json().id, not pm.response.json().user.id

B. You must use pm.variables.set instead of pm.environment.set

C. You forgot to add double curly braces around userId in the next request

D. Environment variables cannot be used in headers

Solution

1. Step 1: Check JSON path correctness

   If the response JSON has user ID at id root, then pm.response.json().user.id is wrong and returns undefined.

2. Step 2: Understand effect of wrong path

   Saving undefined sets empty variable, so {{userId}} is empty in next request causing failure.

3. Final Answer:

   The JSON path is incorrect; user ID is at pm.response.json().id, not pm.response.json().user.id -> Option A

4. Quick Check:

   Correct JSON path = correct variable value [OK]

Hint: Verify JSON path matches response structure exactly [OK]

Common Mistakes:

• Using wrong JSON path causing undefined variable
• Confusing pm.variables.set with pm.environment.set
• Forgetting to use {{}} in next request
• Thinking environment variables can't be used in headers

5. You want to extract a session ID from a login response and use it in the next request's URL as a path parameter. The login response JSON is:

{"session": {"id": "sess789"}}

Which is the correct way to extract and use this session ID in the next request URL https://api.example.com/data/{{sessionId}}?

hard

A. In test script: pm.environment.set('sessionId', pm.response.json().session.id); Use URL with {{sessionId}}

B. In test script: pm.variables.set('sessionId', pm.response.json().session.id); Use URL with {{sessionId}}

C. In test script: pm.environment.set('sessionId', pm.response.json().id); Use URL with {{sessionId}}

D. In test script: pm.environment.set('sessionId', pm.response.json().sessionId); Use URL with {{sessionId}}

Solution

1. Step 1: Extract session ID correctly from nested JSON

   The session ID is at pm.response.json().session.id, so use this path to extract it.

2. Step 2: Save to environment variable and use in URL

   Use pm.environment.set('sessionId', ...) to save it, then use {{sessionId}} in the next request URL.

3. Final Answer:

   In test script: pm.environment.set('sessionId', pm.response.json().session.id); Use URL with {{sessionId}} -> Option A

4. Quick Check:

   Correct path + environment set + {{var}} usage [OK]

Hint: Match JSON path exactly and use pm.environment.set [OK]

Common Mistakes:

• Using wrong JSON path like pm.response.json().id
• Using pm.variables.set which is temporary
• Using incorrect variable name in URL
• Extracting from wrong JSON key