API Chaining — End-to-End Flow

Practice complete end-to-end API workflows by storing values from one response and reusing them in subsequent requests.

Use:

pm.environment.set()
{{variables}}

to pass dynamic values between requests.

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Exercise 1: Login & Extract Token

Generate the authentication token.

Exercise 2: Create Resource & Extract ID

Create a resource and store its ID.

Examples:

  • User ID
  • Booking ID

Exercise 3: Fetch the Resource

Retrieve the resource using the stored ID.

Exercise 4: Update the Resource

Update the resource data.

Exercise 5: Validate Updated Data

Verify that the updated data is reflected correctly.

Exercise 6: Delete the Resource

Delete the resource.

Exercise 7: Validate Deleted Resource

Verify that accessing the deleted resource returns:

404

Exercise 8: Execute Complete End-to-End Flow

Run the complete business workflow.

Exercise 9: Handle Chaining Failure

Handle failures gracefully during API chaining.

Exercise 10: Debug Chaining Failures

Investigate failures occurring during chained execution.

RESTful Booker End-to-End Flow

Practice the following sequence:

  • Login
  • Generate Token
  • Create Booking
  • Store Booking ID
  • Get Booking
  • Update Booking
  • Partial Update
  • Delete Booking
  • Validate Complete Flow

Interview Line

"I implemented complete end-to-end API chaining in Postman."

Negative & Security Testing

Practice defensive API testing.

Exercise 1: Invalid Request Body

Send invalid JSON payloads.

Exercise 2: Missing Mandatory Fields

Validate mandatory-field validation.

Exercise 3: Invalid Headers

Validate missing and incorrect request headers.

Exercise 4: Invalid Authentication

Validate:

  • Invalid Token → 403
  • Missing Token → 401

Exercise 5: SQL Injection Testing

Validate SQL Injection payloads.

Exercise 6: XSS Testing

Validate Cross-Site Scripting payloads.

Exercise 7: Rate-Limit Testing

Practice conceptual rate-limit validation.

Exercise 8: Access Forbidden APIs

Validate access to restricted APIs.

Exercise 9: Invalid Resource IDs

Validate invalid booking IDs and other invalid resource identifiers.

Exercise 10: Boundary Value Testing

Validate boundary-value scenarios.

Exercise 11: Content-Type Validation

Validate content-type mismatch scenarios.

Exercise 12: Error Validation

Verify:

Goal

Ensure APIs reject invalid input using:

  • Correct Status Codes
  • Consistent Error Messages
  • Secure Validation

Data-Driven Testing (CSV)

Practice executing APIs using multiple datasets through the Collection Runner.

Exercise 1: Execute Multiple Users

Run the same API using multiple user datasets.

Exercise 2: Bulk API Testing

Create a CSV containing multiple bookings.

Execute booking creation using every row.

Exercise 3: Validate Every Iteration

Verify every iteration independently.

Exercise 4: Handle Partial Failures

Validate behavior when only some datasets fail.

Exercise 5: Validate Edge Data

Execute APIs using edge-case datasets.

Exercise 6: Maintain Independent Test Data

Prevent cross-test data contamination.

Exercise 7: Reset Test Data

Clean up test data after execution.

Exercise 8: Handle Dependent Data

Manage dependent values within CSV datasets.

Exercise 9: Validate Reporting Accuracy

Verify execution reports for every iteration.

Exercise 10: Optimize Execution

Improve performance of data-driven execution.

Purpose

Data-driven testing allows one request to validate many input combinations by executing the same API against multiple rows of test data.

Demo-API Mapping

API Chaining

Practice using:

  • RESTful Booker
  • ReqRes

Exercises include:

  • Login
  • Token Generation
  • Create Resource
  • Store ID
  • Update
  • Delete
  • Validate 404

Negative & Security Testing

Practice using:

  • RESTful Booker

Exercises include:

  • Invalid Dates
  • Missing Fields
  • Invalid Token
  • Invalid Booking ID
  • SQL Injection
  • XSS Payloads

Data-Driven Testing

Practice using:

  • ReqRes
  • RESTful Booker

Execute:

  • Multiple Users
  • Multiple Bookings
  • CSV-Based Collection Runner Execution

FAQs

What Is API Chaining in Postman?

API chaining stores values such as authentication tokens and resource IDs using:

 
pm.environment.set()
 

These values are reused using:

 
{{variables}}
 

This enables complete end-to-end business workflows.

How Do You Verify a Deleted Resource?

After deleting the resource, send another request to retrieve it.

Validate that the API returns:

404

Which Negative & Security Scenarios Should Be Practiced?

Practice:

  • Invalid Request Body
  • Missing Fields
  • Missing Headers
  • Invalid Headers
  • Invalid Token
  • Missing Token
  • SQL Injection
  • XSS
  • Invalid IDs
  • Boundary Values
  • Error Codes
  • Error Response Schema

How Is Data-Driven Testing Performed in Postman?

Attach a CSV or JSON file to the Collection Runner.

Execute every row independently and validate every iteration.

Maintain independent test data and clean up after execution.

How Should Chaining Failures Be Handled?

Handle missing variables gracefully.

Validate flow consistency and debug the request where the failure occurred.