Common HTTP Methods

When working with web development, APIs, or networking, understanding HTTP methods is one of the most important fundamentals. HTTP (Hypertext Transfer Protocol) defines a set of request methods that specify the action to be performed on a resource. These methods are verbs like GET, POST, PUT, PATCH, and DELETE that clearly describe what the client wants to do with a particular resource hosted on a server.

In this comprehensive post, we will take a deep dive into the most commonly used HTTP methods. We will explore their purpose, use cases, technical details, advantages, and examples. This article is designed to be highly detailed, aiming for approximately 3000 words, so that beginners and advanced learners alike can gain a complete understanding of how these methods work.

---

Introduction to HTTP Methods

HTTP methods are commands that tell the server what action should be taken for a particular request. Each method has a specific role, and using the wrong method can result in incorrect behavior or even security vulnerabilities.

The most commonly used HTTP methods are:

1. GET – Fetch data from the server.
2. POST – Send data to the server to create something new.
3. PUT/PATCH – Update existing data on the server.
4. DELETE – Remove data from the server.

These methods form the foundation of RESTful APIs and modern web applications. Let us now break them down in detail.

---

The GET Method

Definition

The GET method is used to request data from a server. It is a read-only operation, meaning it should not alter the state of the resource in any way.

Characteristics of GET

• Safe method: Does not change data on the server.
• Idempotent: Multiple identical requests will have the same effect.
• Parameters are usually sent in the query string of the URL.
• Typically used to fetch resources like web pages, JSON data, or files.

Example of a GET Request

GET /users?id=10 HTTP/1.1
Host: api.example.com
Accept: application/json

The server responds with the requested data:

{
  "id": 10,
  "name": "John Doe",
  "email": "[email protected]"
}

Use Cases of GET

1. Loading a webpage in the browser.
2. Fetching user details from an API.
3. Searching for products in an e-commerce application.
4. Downloading files or images.

Advantages of GET

• Simple and efficient.
• Easy to bookmark URLs with query parameters.
• Works well with caching, making it faster for repeated requests.

Limitations of GET

• Cannot carry large amounts of data because query strings have length limits.
• Sensitive information (like passwords) should not be passed in query strings since URLs may be logged or cached.

---

The POST Method

Definition

The POST method is used to send data to the server to create a new resource. Unlike GET, POST requests include a request body containing the payload.

Characteristics of POST

• Not safe: Can modify or create resources on the server.
• Not idempotent: Submitting the same request multiple times may result in multiple new records.
• Data is usually sent in formats like JSON, form data, or multipart files.

Example of a POST Request

POST /users HTTP/1.1
Host: api.example.com
Content-Type: application/json

{
  "name": "Alice Smith",
  "email": "[email protected]",
  "password": "securepassword"
}

The server responds with a confirmation:

{
  "id": 101,
  "name": "Alice Smith",
  "email": "[email protected]",
  "message": "User created successfully"
}

Use Cases of POST

1. User registration or login.
2. Submitting forms on websites.
3. Adding a new product to an inventory system.
4. Uploading files.

Advantages of POST

• Can handle large amounts of data.
• Data is not exposed in the URL.
• Supports complex payloads like JSON or file uploads.

Limitations of POST

• Cannot be cached easily.
• If repeated accidentally, can lead to duplicate data entries.
• More bandwidth-intensive than GET in some cases.

---

The PUT Method

Definition

The PUT method is used to update an existing resource on the server. Unlike POST, which creates new resources, PUT modifies resources that already exist.

Characteristics of PUT

• Idempotent: Repeating the same request will produce the same result.
• Replaces the entire resource with the new data sent.
• Requires the client to send the complete representation of the resource.

Example of a PUT Request

PUT /users/101 HTTP/1.1
Host: api.example.com
Content-Type: application/json

{
  "id": 101,
  "name": "Alice Johnson",
  "email": "[email protected]"
}

Server response:

{
  "id": 101,
  "name": "Alice Johnson",
  "email": "[email protected]",
  "message": "User updated successfully"
}

Use Cases of PUT

1. Updating a user’s profile information.
2. Replacing details of a product in an online store.
3. Modifying configuration settings.

Advantages of PUT

• Consistent results because of idempotency.
• Works well for resources where the complete record is updated frequently.

Limitations of PUT

• Requires sending the entire resource representation, even if only a small change is needed.
• More bandwidth-heavy compared to PATCH.

---

The PATCH Method

Definition

The PATCH method is used to partially update a resource on the server. Unlike PUT, it does not replace the whole resource—only the fields specified are updated.

Characteristics of PATCH

• Not always idempotent (depends on server implementation).
• Useful when updating only part of a resource.
• More efficient than PUT when making small updates.

Example of a PATCH Request

PATCH /users/101 HTTP/1.1
Host: api.example.com
Content-Type: application/json

{
  "email": "[email protected]"
}

Server response:

{
  "id": 101,
  "name": "Alice Johnson",
  "email": "[email protected]",
  "message": "User email updated successfully"
}

Use Cases of PATCH

1. Updating a single field in a database record.
2. Changing just the status of an order (e.g., from “pending” to “shipped”).
3. Modifying one preference setting in a user profile.

Advantages of PATCH

• Saves bandwidth by sending only partial data.
• Faster updates compared to PUT for small changes.

Limitations of PATCH

• Not universally supported by all APIs.
• Complexity increases if the update logic is not simple.

---

The DELETE Method

Definition

The DELETE method is used to remove a resource from the server.

Characteristics of DELETE

• Idempotent: Deleting the same resource multiple times will have the same effect.
• Once successful, the resource should no longer exist on the server.

Example of a DELETE Request

DELETE /users/101 HTTP/1.1
Host: api.example.com

Server response:

{
  "message": "User deleted successfully"
}

Use Cases of DELETE

1. Removing a user account.
2. Deleting a product from an inventory.
3. Clearing files or images stored on a server.

Advantages of DELETE

• Direct and clear action.
• Helps keep resources clean and up-to-date.

Limitations of DELETE

• Cannot be undone unless a soft-delete system is implemented.
• Risk of accidental data loss if not used carefully.

---

Comparing HTTP Methods

It is important to compare these methods to understand when to use which one.

Method	Safe	Idempotent	Typical Use Case	Request Body
GET	Yes	Yes	Fetch data	No
POST	No	No	Create data	Yes
PUT	No	Yes	Replace data	Yes
PATCH	No	Sometimes	Update partially	Yes
DELETE	No	Yes	Remove data	No

---

HTTP Methods in RESTful APIs

REST (Representational State Transfer) is an architectural style for designing APIs. In REST, resources are identified by URLs, and HTTP methods are used to perform operations on those resources.

For example, managing users in a REST API might look like this:

• GET /users – Fetch all users.
• GET /users/101 – Fetch a specific user.
• POST /users – Create a new user.
• PUT /users/101 – Update the entire user record.
• PATCH /users/101 – Update part of the user record.
• DELETE /users/101 – Delete a user.

This consistent usage makes RESTful APIs intuitive and easy to use.

---

Best Practices for Using HTTP Methods

1. Always use the correct method for the intended action.
2. Do not use GET requests to modify server data.
3. Ensure idempotent methods (PUT, DELETE) behave consistently.
4. Use PATCH for partial updates to save bandwidth.
5. Avoid exposing sensitive data in URLs.
6. Secure all methods with proper authentication and authorization.
7. Implement meaningful responses and status codes.

---

Common Mistakes with HTTP Methods

1. Using POST for all operations instead of following REST conventions.
2. Sending sensitive data in GET query strings.
3. Confusing PUT with PATCH and misusing them.
4. Forgetting that DELETE operations are irreversible.

---