How to Send Different Types of Requests (GET, POST, PUT, DELETE) in Postman

Postman is a powerful tool that simplifies the process of testing APIs by allowing developers to send different types of HTTP requests. In this comprehensive guide, we’ll walk through how to send GET, POST, PUT, and DELETE requests in Postman, focusing on their role in API testing and API development. Whether you're a beginner or an experienced developer, this guide will help you understand how to test API endpoints and perform data manipulation effectively.

Understanding HTTP Methods: GET, POST, PUT, DELETE

Before diving into how to send requests in Postman, it's essential to understand the different HTTP methods used in web development. These methods dictate how clients and servers interact in the context of a RESTful API. Here's a brief overview of the key request types:

• GET: Retrieves data from the server without modifying anything. This is commonly used for fetching resources.
• POST: Sends data to the server to create a new resource. It is often used for form submissions and data creation.
• PUT: Updates an existing resource on the server. It generally replaces the entire resource with new data.
• DELETE: Removes a resource from the server.

How to Send GET Requests in Postman

The GET method is the most commonly used HTTP method for retrieving data from an API. In Postman, sending a GET request is simple and straightforward.

Steps to Send a GET Request in Postman

1. Open Postman and select the GET method from the dropdown next to the URL field.
2. Enter the URL of the API endpoint you want to request data from.
3. Click Send to send the request.

GET Request Example

For instance, if you're testing a RESTful API that retrieves information about users, you can use the following URL:

📄
https://api.example.com/users

Testing API Endpoints with GET Requests

• Use GET requests to fetch data from a database, such as retrieving all users or fetching details about a specific user.
• Test the success status code, such as 200 OK, to verify that the request was successful.
• Check response times and ensure that the data returned is correct and formatted properly.

How to Send POST Requests in Postman

The POST method is used to send data to the server for the creation of new resources. It is commonly used for submitting forms or creating new objects in databases.

Steps to Send a POST Request in Postman

1. Choose the POST method from the dropdown next to the URL field.
2. Enter the URL for the API endpoint that accepts the data.
3. In the Body tab, select the data format (e.g., JSON, form-data) and enter the data to be sent.
4. Click Send to submit the request.

POST Request Example

For creating a new user, you might use the following API endpoint with JSON data in the body:

📄
POST https://api.example.com/users

📄

{
  "name": "John Doe",
  "email": "john.doe@example.com",
  "password": "securepassword"
}

Testing API Endpoints with POST Requests

• Use POST requests for creating new entries in the database.
• Verify that the server returns a 201 Created status code when a new resource is successfully created.
• Test data validation by submitting invalid data and checking for error responses.

How to Send PUT Requests in Postman

The PUT method is used to update an existing resource on the server. Unlike POST, which creates new resources, PUT replaces the entire resource with the new data provided.

Steps to Send a PUT Request in Postman

1. Select the PUT method from the dropdown next to the URL field.
2. Enter the URL for the resource you want to update.
3. In the Body tab, enter the new data to replace the existing resource.
4. Click Send to submit the request.

PUT Request Example

If you want to update an existing user's email address, the request might look like this:

📄
PUT https://api.example.com/users/123

📄

{
  "name": "John Doe",
  "email": "new.email@example.com"
}

Testing API Endpoints with PUT Requests

• Use PUT requests to modify existing resources with new data.
• Ensure that the response status code is 200 OK when the resource is successfully updated.
• Verify that the updated resource is correct by performing a subsequent GET request.

How to Send DELETE Requests in Postman

The DELETE method is used to remove a resource from the server. When you send a DELETE request, you are requesting the server to delete the resource identified by the URL.

Steps to Send a DELETE Request in Postman

1. Choose the DELETE method from the dropdown next to the URL field.
2. Enter the URL for the resource you want to delete.
3. Click Send to send the request.

DELETE Request Example

To delete a user with a specific ID, the request might look like this:

📄
DELETE https://api.example.com/users/123

Testing API Endpoints with DELETE Requests

• Use DELETE requests to remove resources from the server.
• Ensure that the response returns a 200 OK or 204 No Content status code after a successful deletion.
• Test the absence of deleted resources by performing a GET request after the DELETE request and verifying that the resource no longer exists.

FAQs About Sending Requests in Postman

What is the difference between GET and POST requests in Postman?

GET requests are used to retrieve data from the server without modifying it, while POST requests are used to send data to the server to create new resources.

Can I send data in a GET request in Postman?

Yes, you can send data in a GET request, but it is typically sent as query parameters in the URL rather than in the request body. For example: GET https://api.example.com/users?name=John.

How do I test different API endpoints in Postman?

You can test different API endpoints by entering the appropriate URL in the Postman request URL field and choosing the correct HTTP method (GET, POST, PUT, DELETE) for each test case.

What should I check after sending a POST request in Postman?

After sending a POST request, you should verify that the server returns a 201 Created status code, and check that the new resource has been created correctly by performing a GET request to retrieve it.

Conclusion

Postman is a valuable tool for testing and interacting with APIs. By understanding how to send different types of requests like GET, POST, PUT, and DELETE, you can effectively test API endpoints and manipulate data. Whether you are working on API development or web development, mastering these HTTP methods will help you build and maintain robust APIs and improve the quality of your software projects.