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

Recall

What are Variables?

Variables in Postman are used to store values that can be reused across requests, collections, or environments.

Instead of hardcoding values such as URLs, tokens, IDs, or usernames inside requests, variables allow testers to store these values in one place and reference them dynamically.

Transition to Technical Concept

  • Environments in Postman are used to store variables that can change depending on where the API is being tested.
  • While testing an API, the base URL, tokens, or user credentials might be different for Development, Testing, or Production environments.
  • 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, and helps avoid mistakes when working with multiple setups.
  •  For instance, a tester can create separate environments such as Dev, QA, and Production, each containing its own base URL and authentication details.

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

From current ppt add Creating an Environment, Switching between Environments and continue with below content

Chaining API Requests in Postman

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

For example:

  • When a user logs in, the system returns an authentication token.

In many real-world applications, APIs do not work independently. One request often generates data that is required for the next request

Chaining API Requests in Postman

  • This token is then used in other API requests to access protected resources.
  • Instead of referring this value manually, Postman allows you to capture it automatically and use it in the next requests

Chaining API Requests in Postman

In Postman, request chaining is usually done by extracting values from the response of one request and storing them in variables.

These variables can then be used in headers, parameters, or request bodies of other API calls.

This approach makes testing smoother and helps simulate real application flows.

One of the common ways to implement chaining is through test scripts in Postman.

Chaining API Requests in Postman

After a request is executed, a script can capture a value from the response using JavaScript and store it as a variable.

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

The id returned in the response is stored in an environment variable called userId.

This variable can then be used in the next API request like this:

{{userId}}

Chaining API Requests in Postman

Request chaining is especially useful when testing end-to-end API workflows.

A common API flow might look like this:

Chaining API Requests in Postman

To make chaining effective, it is important to:

  • Identify which response values are required for later requests

  • Extract those values using scripts

  • Store them in appropriate variables

  • Reference those variables in subsequent requests

In this case, values like user ID and token are captured from earlier responses and reused in later requests.

 It helps when running collections or automated test runs using tools like the Collection Runner or Newman.

Since the required values are automatically passed from one request to another, the entire API workflow can run without manual intervention.

Summary

4

Reduces effort, boosts efficiency, and improves reliability.

3

Request chaining connects API calls into a workflow.

2

They avoid manual changes by enabling easy environment switching.

1

Postman environments store variables for different setups (Dev, QA, Prod).

Quiz

Which Postman feature is commonly used to capture values from a response for chaining?

A. Headers

B. Test Scripts

C. Authorization tab

D. Cookies

Quiz-answer

Which Postman feature is commonly used to capture values from a response for chaining?

A. Headers

B. Test Scripts

C. Authorization tab

D. Cookies

API Testing with POSTMAN: Using Environment Variables

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API Testing with POSTMAN: Using Environment Variables

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