API Testing with POSTMAN

Using Environment Variables

Learning Outcome

4

How to use Environment

3

How to create Environment

2

Why do we need Environments

1

Chaining API RequestsWhat is Environment

Environments in Postman

  • Environments in Postman are used to store variables that can change depending on where the API is being tested
  • Environment is a set of key-value pairs

Definition

  • Base URL, tokens, or user credentials might be different for Development, Testing, or Production

  • Instead of manually updating these values every time, Postman allows you to store them as variables inside an environment

  • This makes testing faster, Reduces manual effort

  • Helps avoid mistakes when working with multiple setups

Why Environments are Used

Chaining API Requests in Postman

Understanding the Concept

API request chaining is a technique where the output of one API request is used as an input for another request

Definition:

APIs do not work independently in real-world applications

One request generates data required for the next request

Chaining API Requests in Postman

For example,

Key Idea

when a user logs in

This token is then used in other API requests to access protected resources

  • And use it in the next requests

  • Postman allows you to capture it automatically

  • Instead of referring this value manually

 the system returns an authentication token

 How Request Chaining Works

Extract values from the response of one request

Store them in variables

Use those variables in:

Helps simulate real application flows

Makes testing smoother

  • Headers

  • Parameters

  • Request bodies

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1

3

2

5

4

Using Test Scripts for Chaining

  • Implemented using test scripts in Postman

  • After request execution

let responseData = pm.response.json();
pm.environment.set("userId", responseData.id);

 Example

Response returns id

Stored in environment variable: userId

Used in next API request

Script captures value from response

Stores it as a variable

Uses JavaScript

Real-World API Workflow

Create a user → API returns user ID

Login user → API returns authentication token

Use the token to access profile details

Update the user profile using the same user ID

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4

3

2

Key Point

  • Values like user ID and token are reused across requests

Benefits of Request Chaining

Helps in end-to-end API testing

Useful for running collections

Works with

  • Collection Runner
  • Newman

No manual intervention required

Entire workflow runs automatically

Best Practices

Identify required response values

Extract values using scripts

Store in appropriate variables

Reference in next requests

Summary

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3

2

1

Environments in Postman allow testers to store variables such as base URLs, tokens, and credentials that may differ across Dev, QA, or Production setups

They help avoid manual changes in requests by allowing users to switch between environments easily

Request chaining helps connect multiple API calls together so they behave like a real application workflow

It reduces manual effort, improves testing efficiency, and makes API testing more reliable, especially when working with complex API flows

Quiz

Which of the following values is commonly stored in a Postman Environment?

A. Base URL

B. API Token

C. User Credentials

D. All of the above

Quiz-Answer

Which of the following values is commonly stored in a Postman Environment?

A. Base URL

B. API Token

C. User Credentials

D. All of the above

Using Environment Variables

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Using Environment Variables

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