Using Postman Leveraging Response Data For Seamless API Requests

Postman Use Response in Next Request
Postman is a powerful tool for testing APIs, and it allows you to use data from the response of one request in subsequent requests. This can be particularly useful for passing authentication tokens, IDs, or other data between requests. Here’s a step-by-step guide on how to implement this feature, often referred to as “postman use response in next request.”

Step 1: Capture the Response Data
Make the Initial Request: First, create and send the request that will return the data you need for subsequent requests.
Add a Script to Capture Data: Use Postman’s
Tests
tab to write a script that captures the necessary data from the response. For example, if you're capturing a token from a JSON response:
javascript
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// Assuming the response JSON has a field called 'token' var jsonData = pm.response.json(); pm.environment.set("authToken", jsonData.token)
This script extracts the
token
value from the response JSON and sets it as an environment variable called
authToken
.
Step 2: Use the Captured Data in the Next Request
Create the Next Request: Create a new request or open an existing one where you want to use the captured data.
Insert the Environment Variable: Use the environment variable you set in the previous step. You can insert it into the request headers, body, URL, or wherever it’s needed.

For example, if you need to pass the token as a Bearer token in the headers:
Go to the
Headers
tab of your request.
Add a new header:
Key:
Authorization
Value:
Bearer {{authToken}}
Using
{{authToken}}
tells Postman to use the value of the
authToken
environment variable.
Step 3: Execute the Sequence
Ensure the Environment is Selected: Make sure the environment containing the
authToken
variable is selected in the environment dropdown in the top-right corner of Postman.
Run the Requests: Send the requests. The first request will set the
authToken
variable, and the subsequent request will use this variable.
Example Scenario
Let’s walk through a practical example where an initial request logs in a user and gets an authentication token, which is then used in a subsequent request to access a protected resource.

Login Request:
URL:
https://api.example.com/login
Method:
POST
Body:
json
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{ "username": "user", "password": "password" }
Tests Script:
javascript
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var jsonData = pm.response.json(); pm.environment.set("authToken", jsonData.token);
Protected Resource Request:
URL:
https://api.example.com/protected
Method:
GET
Headers:
Authorization:
Bearer {{authToken}}
Running in Collection Runner
For more complex workflows, consider using Postman’s Collection Runner to execute a series of requests automatically:

Create a Collection: Add both requests to a collection.
Run the Collection: Open the Collection Runner, select the collection, and run it. Postman will execute the requests in sequence, passing data between them as defined.
Summary
By capturing data from one request and using it in subsequent requests, Postman allows for powerful and flexible API testing workflows. This method, often referred to as “postman use response in next request,” can be used to handle authentication tokens, dynamic data, and more, streamlining your API testing process.