# Web Services With Only net/http

Here's a thing that surprises people coming to Go: you often don't need a web framework at all. The
standard library's `net/http` already gives you a production-grade HTTP server, a router, and everything
to read requests and write responses. [Gin](/guides/gin-from-zero), [Echo](/guides/echo-from-zero), and
[chi](/guides/chi-from-zero) are conveniences *over this* - and once you've built a real JSON API with
only the standard library, every one of them reads as "net/http with some boilerplate removed." This is
the **roots** guide: learn it and the frameworks stop being magic.

The mental model is three standard types. A **`Handler`** is anything with `ServeHTTP(w, r)` - your code
that handles one request (a plain function becomes one via `http.HandlerFunc`). A **`ServeMux`** is the
router: it maps URL patterns to handlers. And the **`Server`** ties an address to a handler and listens.
That's the whole architecture: *the mux routes a request to a handler, the handler writes the response.*
Middleware? Just a function that wraps a `Handler` and returns a new one. Hold those, and you can read any
Go web codebase - framework or not.

> 📝 This teaches the **standard library** - it assumes you know **Go** (functions, interfaces, structs,
> `error` - [Go From Zero](/guides/go-from-zero)) and basic **HTTP** (methods, status, headers -
> [HTTP, Explained](/guides/http-explained)). It's the Go parallel to
> [WSGI & ASGI Explained](/guides/wsgi-and-asgi-explained) (Python's foundation) and is best read before
> or alongside the framework guides so you can see what each one adds. Examples run as plain Go programs.

## How to read this

Short and foundational - read in order. It builds a bare server, then a full JSON API (a small
**messages** service), then maps it onto the frameworks. Uses modern Go (1.22+) routing. Phases carry
difficulty badges.

## The phases

1. **[The net/http Mental Model](01-the-mental-model.md)** 🟢 - `Handler`, `ServeMux`, `Server`, and how one request flows through them.
2. **[Handlers & Routing by Hand](02-handlers-and-routing.md)** 🟡 - `HandlerFunc`, registering routes, and the Go 1.22 method+path patterns.
3. **[Reading Requests, Writing JSON](03-requests-and-json.md)** 🟡 - params, query, body decoding, and writing JSON responses with the right status.
4. **[Middleware Is Just a Wrapper](04-middleware-is-a-wrapper.md)** 🟡 - `func(http.Handler) http.Handler`, chaining, and logging/auth examples.
5. **[A JSON REST API With No Framework](05-rest-api-no-framework.md)** 🔴 - full CRUD for the messages resource using only the standard library.
6. **[Structure, Context & Graceful Shutdown](06-structure-and-shutdown.md)** 🔴 - dependency wiring, `context`, timeouts, and shutting down cleanly.
7. **[What the Frameworks Add](07-what-frameworks-add.md)** 🟢 - mapping Gin/Echo/chi back onto this, and when you genuinely don't need them.

> The throughline: **mux routes to handler, handler writes response, middleware wraps handlers.** That's
> net/http, and that's the skeleton inside every Go web framework.