Build a Server With Only node:http

Before you reach for Express or Fastify, it's worth knowing this: Node ships with everything you need to run a real web server in its built-in node:http module. Express and Fastify are conveniences over this - and once you've built a JSON API with only the standard library, every Node framework reads as "node:http with the boilerplate removed." This is the roots guide: learn it and app.get(...) stops being magic, because you'll have written the thing it wraps.

The mental model is small. http.createServer gives you a server; you hand it one request listener

• a function (req, res) called for every request. req is a readable stream of the incoming request (method, url, headers, body); res is a writable stream you set a status + headers on and write the response to. There's no router and no middleware - you write a router by switching on req.method and req.url, and "middleware" is just a function you call before your handler. Hold "a server calls your (req, res) function for each request, and you do the rest," and the whole Node web stack opens up.

📝 This is a roots guide - it assumes JavaScript/Node: functions, async/await, callbacks, streams basics (JavaScript From Zero) and basic HTTP (HTTP, Explained). It's the JS parallel to the Go net/http roots guide and is best read before or alongside Express so you can see what it adds. Examples run with node.

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 Express. Phases carry difficulty badges.

The phases

1. The node:http Mental Model 🟢 - createServer, the (req, res) listener, and how a request flows.
2. Handling Requests & Responses 🟡 - method/url/headers, reading the body, and writing JSON with a status.
3. Routing by Hand 🟡 - switching on method + path, and why a real router exists.
4. Middleware Is Just a Function 🟡 - wrapping handlers, and the chain Express formalizes.
5. A JSON REST API With No Framework 🔴 - full CRUD for the messages resource, standard library only.
6. Async, Streams & Structure 🔴 - promises in handlers, streaming, graceful shutdown, and layout.
7. What Express Adds 🟢 - mapping Express back onto this, and when you don't need a framework.

The throughline: http.createServer calls your (req, res) function per request; routing and middleware are code you write. That's node:http, and it's the skeleton inside every Node framework.