[Part 2]Getting Started with Manual API Testing Using Postman

Introduction

Postman is a powerful tool for manually testing APIs, allowing users to create, send, and inspect API requests efficiently. This module covers the foundational skills needed to navigate Postman, create API requests, use environments, and manage authentication.

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Lesson 1: Navigating the Postman Interface

Concept:
Familiarizing yourself with Postman’s interface to streamline API testing workflows.

Key Topics:

• Workspace: Organizing API collections and requests.
• Collections: Grouping related API requests.
• Request Builder: Constructing and modifying API requests.
• Response Viewer: Inspecting API responses, headers, and status codes.

Example:
Using the Request Builder to send a GET request and inspect the response in the Response Viewer.

Pro Tip: Use collections to store frequently used requests for easy access.

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Lesson 2: Creating Your First API Request

Concept:
Step-by-step guide to making an API request using Postman.

Key Topics:

• Step 1: Open Postman and create a new request.
• Step 2: Choose an HTTP method (GET, POST, PUT, DELETE).
• Step 3: Enter the API endpoint URL.
• Step 4: Add headers, query parameters, or authentication tokens.
• Step 5: Click Send and review the response.

Example Request:

GET https://api.example.com/users/123

Pro Tip: Start with simple GET requests before moving to more complex API calls.

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Lesson 3: Sending API Requests & Inspecting Responses

Concept:
Understanding response structures and validating API responses.

Key Topics:

• Status Codes: 200 OK, 201 Created, 400 Bad Request, 404 Not Found, 500 Internal Server Error.
• Headers: Metadata such as Content-Type and Authorization.
• Body Formats: JSON, XML, plain text.
• Response Time: Measuring API response performance.

Example Response:

{
  "id": 123,
  "name": "John Doe",
  "email": "[e-mail]"
}

Pro Tip: Always check response status codes to debug API issues effectively.

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Lesson 4: Using Postman Environments for Configuration Management

Concept:
Using environments and variables to manage multiple testing setups.

Key Topics:

• Creating Environments: Set up configurations for Dev, Staging, Production.
• Using Variables: Store API URLs, tokens, and reusable values.
• Switching Environments: Easily test the same request across different servers.

Example Variable Usage:

GET {{base_url}}/users/{{user_id}}

Pro Tip: Use environment variables to eliminate hardcoded values in API requests.

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Lesson 5: Query Parameters, Headers, and Authentication Tokens

Concept:
Enhancing API requests using parameters, headers, and authentication methods.

Key Topics:

• Query Parameters: Filtering results dynamically (e.g., ?name=John).
• Headers: Specifying metadata like Content-Type: application/json.
• Authentication: API Key, Bearer Token, OAuth 2.0.

Example:

GET https://api.example.com/users?status=active
Authorization: Bearer <token>

Pro Tip: Always use secure authentication methods when testing protected APIs.

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Lesson 6: Organizing API Requests in Postman Collections

Concept:
Managing multiple API requests effectively using collections and folders.

Key Topics:

• Creating Collections: Group API requests for better organization.
• Adding Requests: Store frequently tested endpoints.
• Using Folders: Categorize requests by feature or functionality.
• Running Collections: Automate sequential request execution.

Example Workflow:

• Create a User API Collection.
• Add requests: GET /users, POST /users, DELETE /users/123.
• Use Collection Runner to execute all requests in sequence.

Pro Tip: Organize API requests in collections to improve efficiency and collaboration.

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Conclusion

This module introduced the essential skills for manual API testing with Postman. You learned how to navigate Postman’s interface, create API requests, inspect responses, manage configurations, and organize tests efficiently.

Key Takeaways:

• Postman simplifies API request creation and response validation.
• Use status codes, headers, and body content to verify API behavior.
• Manage configurations effectively using Postman environments.
• Organize API tests in collections for better structure and automation.

What’s Next?
In the next module, we will explore building robust API tests with Postman, learning how to write assertions, create test suites, and automate API validations.

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