HTTP Methods Tutorial

HTTP (Hypertext Transfer Protocol) defines a set of request methods to indicate the desired action to be performed for a given resource. These methods are fundamental to web development and RESTful APIs.

1. GET

Purpose: Retrieve data from the server.
Characteristics:
Safe and idempotent (does not modify data).
Parameters are sent in the URL (query string).
Example:
GET /users?id=123

2. POST

Purpose: Submit data to the server to create a resource.
Characteristics:
Not idempotent (can create multiple resources).
Data is sent in the request body.
Example:
POST /users with JSON body { "name": "Alice" }

3. PUT

Purpose: Update or replace a resource.
Characteristics:
Idempotent (repeated requests have the same effect).
Data is sent in the request body.
Example:
PUT /users/123 with JSON body { "name": "Bob" }

4. PATCH

Purpose: Partially update a resource.
Characteristics:
Not necessarily idempotent.
Only the fields to update are sent in the request body.
Example:
PATCH /users/123 with JSON body { "email": "bob@example.com" }

5. DELETE

Purpose: Remove a resource from the server.
Characteristics:
Idempotent.
Example:
DELETE /users/123

6. HEAD

Purpose: Same as GET, but only retrieves headers (no body).
Use Case: Check if a resource exists, get metadata.

7. OPTIONS

Purpose: Describe the communication options for the target resource.
Use Case: Discover allowed methods, CORS preflight requests.

8. TRACE

Purpose: Echo the received request, mainly for debugging.

9. CONNECT

Purpose: Establish a tunnel to the server, typically for HTTPS.

Summary Table

Method	Safe	Idempotent	Typical Use
GET	Yes	Yes	Retrieve data
POST	No	No	Create resource
PUT	No	Yes	Replace resource
PATCH	No	No/Yes	Partial update
DELETE	No	Yes	Delete resource
HEAD	Yes	Yes	Headers only
OPTIONS	Yes	Yes	Discover methods
TRACE	Yes	Yes	Debugging
CONNECT	No	No	Tunnel (e.g., HTTPS proxy)