# HTTP, Explained

Every time you open a website, two computers have a short, polite conversation: your browser asks for something, a server hands it back. That conversation is HTTP - the language the web speaks. You've relied on it every day without ever being shown how it works, and that's fine until a page returns `404`, a developer mentions a "POST request," or `https://` turns red and you wonder if you're about to be robbed.

This guide is the manual nobody handed you. By the end you'll picture exactly what your browser and a server are saying to each other, read a status code without panic, and understand what that little padlock is actually protecting. No deep networking background needed - we start from the conversation and build up.

## How to read this
- **Want a specific answer right now?** Phase 2 has the status-code table - if you just want to know
  what `404` or `500` means, jump to [Phase 2: Methods & Status Codes](02-methods-and-status-codes.md).
- **Want it to finally make sense?** Read in order. Each phase builds on the last: the conversation
  first, then the words it uses, then the details that ride along.

## The phases
1. **[Request & Response](01-request-and-response.md)** - the core model: your browser sends a
   request, the server sends a response. Plus the anatomy of a URL, the address you're really typing.
2. **[Methods & Status Codes](02-methods-and-status-codes.md)** - the verbs (GET, POST, PUT, DELETE)
   and the three-digit replies (2xx, 3xx, 4xx, 5xx), with a table and how to read a code calmly.
3. **[Headers, Cookies & the S in HTTPS](03-headers-cookies-and-https.md)** - the extra notes each
   message carries, how sites remember you, and what encryption actually buys you.

> This guide stops at the everyday mental model. The deeper machinery - how packets actually travel,
> ports, DNS, and the layers underneath HTTP - lives in its own guides:
> [How the Internet Works](/guides/how-the-internet-works),
> [IP, DNS, and Ports](/guides/ip-dns-and-ports), and [The TCP/IP Model](/guides/tcp-ip-model).
> APIs are built directly on top of HTTP, so a future guide on what an API is will link back here.