What is HTTP and how does the protocol work?

HTTP is the simple request-response protocol the web runs on: the browser asks for something, the server answers, and each exchange stands on its own.

HTTP (Hypertext Transfer Protocol) governs how a client and server exchange data on the web. The flow is deliberately simple:

1. The client (browser) sends an HTTP request.
2. The server processes it.
3. The server returns an HTTP response.

Defining properties:

• Stateless — each request is independent; the server does not, by itself, remember anything about previous requests. (That is exactly why cookies and sessions had to be invented to bolt "memory" on top.)
• Text-based — the messages are human-readable, which makes the protocol easy to inspect and debug.
• Current version is 3.0 — HTTP/3 runs over QUIC (a transport built on UDP) for lower latency.

A typical first visit pairs DNS with HTTP:

Browser                       Server
   |--- DNS query --------> (resolver)
   |<-- IP address --------|
   |--- HTTP request ----->|   GET /index.html
   |<-- HTTP response -----|   200 OK + HTML

The browser first resolves the domain to an IP via DNS, then opens the HTTP conversation with that address.

Go deeper:

• Overview of HTTP (MDN) — the gold-standard primer on the client-server, message-based, stateless model.
• HTTP (Wikipedia) — broader history and the HTTP/1.1 → /2 → /3 evolution.