Mastering CRUD Operations in Postman

Crud Operation in Postman

In this section, we will:

Learn about authentication types in APIs.

Understand common response codes.

Perform CRUD operations using an Open API, JSONPlaceholder, with step-by-step guidance.

Step 1: Explore JSONPlaceholder

JSONPlaceholder is a free online tool for testing and experimenting with APIs. It provides a set of fake APIs that can be used to practice CRUD operations without impacting any real database.

1. Visit JSONPlaceholder: https://jsonplaceholder.typicode.com
2. Go to the homepage and read the usage guide.
3. Familiarize yourself with endpoints like /posts, /comments, /users.

Step 2: Set Up Postman

Postman is an API testing tool that helps developers execute and verify API requests.
1.  Download Postman: https://www.postman.com/downloads/
2.  Install the application and create a free account.

   • Once logged in, you’re ready to test APIs.

Step 3: Authentication Types

Postman is an API testing tool that helps developers execute and verify API requests.
1.  Download Postman: https://www.postman.com/downloads/
2.  Install the application and create a free account.

   • Once logged in, you’re ready to test APIs.

API Key Authentication

Example: Joget APIs use API keys as query parameters or in headers.

Basic Authentication

Example: Oracle APEX uses Base64-encoded username and password in the header.

Token-Based Authentication

Example: Platforms like Dynamics 365 provide a bearer token to access APIs.
How to Configure in Postman:

1.  Go to the Authorization tab.
2.  Select the authentication type (API Key, Basic Auth, Bearer Token, etc.).
3.  Add the required credentials or tokens.

Step 4: Response Codes and Their Meaning

Example:

While testing APIs, understanding response codes is crucial:

1.  200 OK: Successful request.
2.  201 Created: A resource was created successfully.
3.  400 Bad Request: Invalid syntax in the request.
4.  401 Unauthorized: Authentication failed or missing.
5.  404 Not Found: Requested resource doesn’t exist.
6.  500 Internal Server Error: The server encountered an issue.

Step 5: Perform CRUD Operations Using JSONPlaceholder

We’ll use the JSONPlaceholder API for practice. Here’s how to perform CRUD operations:

1. Create (POST)

API Endpoint: https://jsonplaceholder.typicode.com/posts

Steps in Postman:

 

1.  Select the POST method.
2.  In the Body tab, choose raw and set format to JSON.
3.  Add data like:

json
{
“title”: “Hello World”,
“body”: “This is a test post.”,
“userId”: 1
}

Click Send and observe the response.

2. Read (GET)

API Endpoint: https://jsonplaceholder.typicode.com/posts/1

Steps in Postman:

1.  Select the GET method.
2.  Enter the endpoint to fetch a specific post.
3.  Click Send and view the response.

json
{
“title”: “Hello World”,
“body”: “This is a test post.”,
“userId”: 1
}

3. Update (PUT)

API Endpoint: https://jsonplaceholder.typicode.com/posts/1

Steps in Postman:

1. Select the PUT method.
2. In the Body tab, provide updated data:

Json
{
“id”: 1,
“title”: “Updated Title”,
“body”: “This post has been updated.”,
“userId”: 1
}

Click Send and observe the changes.

4. Delete (DELETE)

API Endpoint: https://jsonplaceholder.typicode.com/posts/1

Steps in Postman:

1.  Select the DELETE method.
2.  Enter the endpoint to delete the resource.
3.  Click Send and verify the status code 200 OK.

Why Use Postman?

Postman simplifies API testing by:

  Allowing developers to test API functionality before integrating.
  Providing detailed insights into response codes and errors.
•  Supporting various authentication types to mimic real-world scenarios.
•  Practice and Master APIs
•  Follow the steps above to practice API testing using Postman and JSONPlaceholder. Regular practice will help you confidently integrate APIs into your applications.

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