Building an HTTP server

A server with no framework, routing by hand, reading the body, and when to reach for Express-style libraries.

The raw server

import http from "node:http";

const server = http.createServer(async (req, res) => {
  const url = new URL(req.url, "http://" + req.headers.host);

  if (req.method === "GET" && url.pathname === "/health") {
    res.writeHead(200, { "content-type": "application/json" });
    res.end(JSON.stringify({ ok: true }));
    return;
  }

  if (req.method === "POST" && url.pathname === "/echo") {
    let body = "";
    for await (const chunk of req) body += chunk;
    res.writeHead(200, { "content-type": "application/json" });
    res.end(body || "{}");
    return;
  }

  res.writeHead(404, { "content-type": "application/json" });
  res.end(JSON.stringify({ error: "not found" }));
});

server.listen(process.env.PORT ?? 3000, () => console.log("listening"));

Framework or no framework

// the same idea in Express
import express from "express";
const app = express();
app.use(express.json({ limit: "100kb" }));
app.get("/health", (req, res) => res.json({ ok: true }));
app.post("/echo", (req, res) => res.json(req.body));
app.listen(3000);

Production concerns

• Handle unhandledRejection and uncaughtException by logging and exiting — a corrupted process should restart, not linger.
• Add a graceful shutdown on SIGTERM: stop accepting connections, finish in-flight requests, then exit.
• Put the app behind a reverse proxy or platform (Cloudflare, nginx) for TLS, compression and rate limiting.
• Health endpoints let load balancers remove a bad instance automatically.

FAQ

Related

Files and paths in Node HTTP methods

Last refreshed 2026-09-17.