What are the different HTTP methods used in REST API and how do they work?

Key takeaways

• GET reads, POST creates, PUT replaces, PATCH updates part and DELETE removes a resource.
• GET must not change data, which is why caches and crawlers assume it is safe.
• Disable TRACE and unneeded methods on production servers.

Table of Contents

• What Are HTTP Methods?
• 1. How Does the GET Method Retrieve Data?
• 2. How Does the POST Method Create New Resources?
• 3. PUT Method: Update Existing Resources
• 4. PATCH Method: Partial Update
• 5. How Does the DELETE Method Remove Resources?
• 6. HEAD Method: Metadata Check
• 7. OPTIONS Method: Allowed Methods Discovery
• 8. TRACE Method: Debugging and Diagnostics
• Quick Reference Table of HTTP Methods
• Why Knowing HTTP Methods Matters
• Conclusion

In web development, APIs (Application Programming Interfaces) act as bridges between applications, allowing them to communicate and share data. One core concept that makes APIs work is HTTP methods, standardised instructions used to perform different actions on web resources. These methods define what kind of operation a client (like a browser or app) wants to perform on the server.

If you're learning web development, RESTful APIs, or backend systems, understanding HTTP methods is essential. This guide breaks down the most common HTTP methods used in REST APIs, along with examples and beginner-friendly explanations.

What Are HTTP Methods?

HTTP methods are actions that specify how a client interacts with a resource on a server. RESTful APIs use these methods to perform standard operations like retrieving, creating, updating, and deleting data. They map directly to CRUD operations:

• Create → POST

• Read → GET

• Update → PUT/PATCH

• Delete → DELETE

1. How Does the GET Method Retrieve Data?

• Example: GET /api/customers

• What It Does: Retrieves information from the server.

• Use Case: Displaying customer lists or fetching user profiles.

Description:
GET requests should only retrieve data. They don’t modify anything on the server. GET requests are idempotent, meaning making the same request multiple times has the same effect as making it once.

2. How Does the POST Method Create New Resources?

• Example: POST /api/customers

• What It Does: Sends data to the server to create a new resource.

• Use Case: Registering a new user, submitting a form.

Description:
POST requests send information in the request body. Unlike GET, POST can change server-side data.

3. PUT Method: Update Existing Resources

• Example: PUT /api/customers/123

• What It Does: Updates an entire resource identified by an ID.

• Use Case: Updating a user’s profile information.

Description:
PUT replaces the existing resource with the new data provided. It’s often used for full updates rather than partial changes.

4. PATCH Method: Partial Update

• Example: PATCH /api/customers/1234 { "name": "foobar" }

• What It Does: Updates part of a resource.

• Use Case: Changing only a user’s name or email address.

Description:
PATCH is more efficient than PUT for minor updates because it only changes specified fields rather than the entire resource.

5. How Does the DELETE Method Remove Resources?

• Example: DELETE /api/customers/235

• What It Does: Deletes a resource identified by an ID.

• Use Case: Deleting a user account.

Description:
DELETE requests remove resources. Repeating a DELETE request should have no additional effect, which is why it’s considered idempotent.

6. HEAD Method: Metadata Check

• Example: HEAD /api/customers

• What It Does: Retrieves headers and metadata, without the response body.

• Use Case: Checking if a resource exists before downloading it.

Description:
HEAD is like GET, but faster because it only retrieves headers, not the content.

7. OPTIONS Method: Allowed Methods Discovery

• Example: OPTIONS /api/main.html/1.1

• What It Does: Returns permitted HTTP methods for a given URL.

• Use Case: Finding out what operations are allowed on an endpoint.

Description:
OPTIONS is mainly used by browsers for CORS (Cross-Origin Resource Sharing) preflight requests.

8. TRACE Method: Debugging and Diagnostics

• Example: TRACE /api/main.html

• What It Does: Returns the exact request sent to the server.

• Use Case: Debugging network issues.

Description:
TRACE helps developers understand how a request is processed through intermediary systems like proxies or gateways.

9. CONNECT Method: Establishing Tunnels

• Example: CONNECT www.example.com:433 HTTP/1.1

• What It Does: Creates a tunnel between the client and server.

• Use Case: Used in HTTPS connections for secure communication.

Description:
CONNECT is important for encrypted traffic, as it enables end-to-end encrypted sessions.

Quick Reference Table of HTTP Methods

Why Knowing HTTP Methods Matters

Understanding HTTP methods helps in:

• Building APIs and web applications

• Debugging network traffic using tools like Postman or cURL

• Writing secure applications by enforcing correct request methods

• Optimizing API performance through proper use of methods like HEAD and OPTIONS

Conclusion

HTTP methods are the building blocks of web communication. Whether you're building a REST API or just consuming one, knowing how each method works is essential for effective, secure, and efficient web development.

To take this further with guided labs and an instructor, see our Python Django training in Pune.

Related reading

• What is a real HackerOne Broken Access Control Exploit Worth $5000? Full Writeup Inside
• API Penetration Testing: Securing Your APIs with Postman
• What is Postman, and how to perform API testing using Postman| The Complete Guide

Reference

For the authoritative details, see IETF RFCs.