Modern Web Protocols

HTTP Methods (Verbs)

Method	Purpose	Idempotent	Safe	Body
GET	Retrieve resource	Yes	Yes	No
POST	Create resource	No	No	Yes
PUT	Replace entire resource	Yes	No	Yes
PATCH	Partial update	No	No	Yes
DELETE	Remove resource	Yes	No	Optional

Idempotent: multiple identical requests produce the same result. Safe: does not modify the resource (read-only).

Stateless vs Stateful

HTTP is stateless — the server does not retain client information between requests. Each request is independent.

	Stateless	Stateful
Server memory	None per client	Stores session data
Scalability	Trivial (any server handles any request)	Must route client to same server
Examples	HTTP, REST	FTP, TCP connections

Statelessness is what makes the web scalable. Load balancers can distribute requests to any server in a pool.

WebSockets

WebSocket provides a full-duplex persistent connection over a single TCP socket after an HTTP upgrade handshake.

Client                                 Server
  │── HTTP GET (Upgrade: websocket) ──→
  │←─ 101 Switching Protocols ──────────
  │── bidirectional frames ────────────→
  │←───────────────────────────────────

Feature	HTTP	WebSocket
Direction	Half-duplex (request-response)	Full-duplex
Overhead	Headers per request (500-800 bytes)	2-6 bytes per frame
Persistence	Connection closed after response	Connection stays open
Use case	REST APIs, web pages	Real-time apps, chat, games

Statelessness in Practice

Modern web apps simulate state using:

• Cookies: server sends a token (session ID), client sends it back
• JWT (JSON Web Tokens): self-contained tokens with user info and expiry
• Client-side storage: localStorage, sessionStorage

These shift state management to the client while keeping the server stateless.