HTTP Request Methods & API Testing

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API testing plays a critical role in web development, and a solid understanding of the various HTTP request methods is essential to ensure API functionality and reliability. This article will give you a detailed overview of the standard HTTP request methods, explain their purpose in simple terms, and provide comprehensive examples to help new learners. Let us dive into each method!

Table of contents

• GET method
• POST method
• PUT method
• PATCH method
• DELETE method
• HEAD method
• Importance of HTTP methods in API testing
• Conclusion

GET method

The GET method is mainly used to retrieve data from a server. When you make a GET request, you retrieve data without modifying the server’s resources. It is a secure method that does not change any data on the server, even if you send multiple identical GET requests. 

For example, if you want to retrieve information about a user with the ID 123, make a GET request like this:

GET /api/users?id=123

POST method

The POST method is used when sending data to the server to create new resources. It is similar to filling out a form or submitting further information. When you send a POST request, you ask the server to process the data you provide and create a new resource based on that data. Unlike the GET method, the POST method is not similar. That means multiple identical POST requests can result in various resource creations. 

For example, if you want to create a new user, send a POST request with the user’s data in the request body something like this:

POST /api/users
Content-Type: application/json

{
  "name": "John Doe",
  "email": "john@automateNow.io"
}

PUT method

The PUT method is used when you want to update or replace an existing resource on the server. It’s like replacing an old version of something with a new one. When you send a PUT request, you ask the server to completely replace the existing resource with the one you specify in the request text. 

For example, to update a user with ID 123, you would send a PUT request with the updated user information in the request body something like this:

PUT /api/users/123
Content-Type: application/json

{
  "name": "John Smith",
  "email": "john.smith@automateNow.io"
}

PATCH method

The PATCH method is similar to PUT but is used for partial updates to an existing resource. The idea is to change specific parts of a resource without replacing the entire help. When sending a PATCH request, you ask the server to apply the changes specified in the request body to the existing resource rather than replacing it entirely. 

For example, if you want to update only the user’s email address with ID 123, send a PATCH request with the changed email address in the request body something like this:

PATCH /api/users/123
Content-Type: application/json

{
  "email": "john.smith@automateNow.io"
}

DELETE method

The DELETE method is used to remove a specific resource from the server. It is like eliminating something that you no longer need. When you send a DELETE request, you ask the server to delete the resource identified by the specified URL.

For example, to delete the user with ID 123, you would send a DELETE request like this:

DELETE /api/users/123

HEAD method

The HEAD method is similar to GET but retrieves only the response headers, not the response body. It is useful when you want to check the status and metadata of a resource without retrieving the entire content.

For example, you can use the HEAD method to check whether a resource exists, check the timestamp of the last modification, or collect other header information without downloading the entire content.

Importance of HTTP methods in API testing

• Method verification: Testing each method is critical to verify that the server responds correctly and performs the intended actions. By examining the responses to the various techniques, you can ensure that the server handles each request appropriately.

• Error handling: By testing different methods, you can determine how the API handles errors and returns appropriate error codes. By intentionally sending requests that may result in errors, you can ensure that the API responds with the correct error codes and messages and provides helpful information to customers.

• Security testing: You can verify that the API enforces authentication and authorization for sensitive operations by testing different methods. By sending requests using other techniques and testing the responses, you can ensure that the API adheres to security protocols and permissions, preventing unauthorized access or actions.

Final thoughts on HTTP request methods

HTTP request methods are essential parts of API testing. Testers can better evaluate API functionality, security, and reliability by understanding their purpose and importance. By using different methods and analyzing their responses, testers can ensure that APIs work as expected and deliver reliable and consistent results. So, when conducting your API tests, remember to leverage the power of HTTP request methods to validate and improve the quality of your APIs thoroughly. Have fun with your testing!

This post is part of our comprehensive Postman Mini-Course.