Unleashing the Power of Hattip: Revolutionizing HTTP Server Development

Meet Hattip - Like Express, but for the Future

In the fast-paced realm of web development, flexibility, universality, and efficiency are paramount. Developers are constantly seeking tools that not only streamline their workflow but also empower them to create applications that can run seamlessly across various platforms. Enter Hattip—a groundbreaking set of JavaScript packages designed to revolutionize HTTP server development. In this comprehensive guide, we'll explore the core principles, features, and capabilities of Hattip, shedding light on why it's poised to become the go-to solution for building universal server applications.

Why Hattip?

Gone are the days of writing server code that is tightly coupled to a specific framework or platform. Hattip redefines the landscape by enabling developers to write server applications that can be deployed anywhere—from traditional Node.js environments to cutting-edge serverless platforms like AWS Lambda, Cloudflare Workers, and Vercel. By embracing the principles of universality and modularity, Hattip empowers developers to break free from the constraints of monolithic frameworks and embrace a more flexible, future-proof approach to server-side development.

Introducing Hattip: A Modern Approach to HTTP Servers

At its core, Hattip is more than just a collection of JavaScript packages—it's a philosophy that embraces modern web standards, universal compatibility, modularity, and minimalism. Let's delve into the key features that make Hattip stand out in the crowded landscape of server frameworks:

✨ Modern and Future-Proof

Hattip is built on current and future web standards, leveraging technologies like the Fetch API and WinterCG to ensure compatibility and interoperability across different platforms. By adopting these standards, Hattip future-proofs your applications, ensuring they remain relevant and adaptable as the web ecosystem evolves.

🌍 Universal Compatibility

One of the defining features of Hattip is its universal compatibility. Whether you're running your server code in Node.js, the Edge, Deno, or any other environment, Hattip adapts seamlessly, thanks to its versatile adapter-based design. With adapters available for a wide range of platforms, including Cloudflare Workers, Fastly, Vercel, and more, Hattip empowers you to deploy your applications wherever they're needed without sacrificing consistency or performance.

🧩 Modular and Lightweight

Gone are the days of bloated, monolithic server frameworks. Hattip follows a modular approach, allowing you to use as much or as little of its functionality as you need. From core essentials to advanced middleware and utilities, Hattip offers a rich ecosystem of packages that you can mix and match to suit your project requirements. This minimalist philosophy ensures that you only pay for what you use, resulting in leaner, more efficient server applications.

Getting Started with Hattip

Now that we've covered the fundamentals, let's dive into how you can start building server applications with Hattip. We'll walk through the process of creating a simple HTTP handler and deploying it across different platforms using Hattip's adapters.

// handler.js

// This request handler works anywhere, e.g. Node.js, Cloudflare Workers, and Fastly.

export default (context) => {
  const { pathname } = new URL(context.request.url);
  if (pathname === "/") {
    return new Response("Hello from Hattip.");
  if (pathname === "/about") {
    return new Response(
      "This HTTP handler works in Node.js, Cloudflare Workers, and Fastly.",
  return new Response("Not found.", { status: 404 });

In this example, we've created a simple HTTP handler using Hattip. The handler is passed a context object representing the request context and returns a standard Response object. This handler can be deployed across different platforms, thanks to Hattip's universal compatibility.

Adapters: Bridging the Platform Divide

One of the key strengths of Hattip is its adapter-based architecture, which allows you to run your applications on any platform with ease. Let's explore how you can use Hattip with different platforms using adapters:

Running Hattip on Node.js

// entry-node.js
import { createServer } from "@hattip/adapter-node";
import handler from "./handler.js";

createServer(handler).listen(3000, "localhost", () => {
  console.log("Server listening on http://localhost:3000");

Running Hattip on Cloudflare Workers

// entry-cfw.js
import cloudflareWorkersAdapter from "@hattip/adapter-cloudflare-workers";
import handler from "./handler.js";

export default {
  fetch: cloudflareWorkersAdapter(handler),

Using Hattip with Express.js

// entry-express.js
import { createMiddleware } from "@hattip/adapter-node";
import handler from "./handler.js";
import express from "express";
import oldAndRustyExpressMiddleware from "old-and-rusty-express-middleware";

const hattip = createMiddleware(handler);
const app = express();


app.listen(3000, "localhost", () => {
  console.log("Server listening on http://localhost:3000");

With Hattip's adapters, you can leverage the same codebase across different platforms, eliminating the need to rewrite your server code for each environment.

Middleware System: Powering Your Applications

Hattip's middleware system provides a flexible and powerful way to enhance your server applications. By composing multiple handlers into a single pipeline, you can add functionality such as URL parsing, response modification, error handling, and more. Here's an example of how you can use Hattip's compose function to create a middleware pipeline:

import { compose } from "@hattip/compose";

// Middleware to parse the URL into a URL object
const urlParser = (ctx) => {
  ctx.url = new URL(ctx.request.url);

// Middleware to add an X-Powered-By header
const poweredBy = async (ctx) => {
  const response = await ctx.next();
  response.headers.set("X-Powered-By", "Hattip");
  return response;

// Example handlers
const homeHandler = (ctx) => {
  if (ctx.url.pathname === "/") {
    return new Response("Home");

const fooHandler = (ctx) => {
  if (ctx.url.pathname === "/foo") {
    return new Response("Foo");

const barHandler = (ctx) => {
  if (ctx.url.pathname === "/bar") {
    return new Response("Bar");

export default compose(

By composing middleware functions, you can create robust and feature-rich server applications with Hattip.

Extending Hattip with Packages

Hattip's modular architecture makes it easy to extend and customize your server applications. Whether you need additional adapters, bundlers, utilities, or middleware, Hattip's ecosystem of packages has you covered. Here's a brief overview of some of the packages available:

  • Adapters: Enable Hattip to run on any platform, including Node.js, Cloudflare Workers, Deno, Express

.js, Fastly, and more.

  • Bundlers: Provide optimized bundlers for different platforms, ensuring seamless deployment of your applications.
  • Utilities and Middleware: From routing and response handling to session management and GraphQL support, Hattip offers a wide range of middleware and utilities to enhance your server applications.


In conclusion, Hattip represents a paradigm shift in the world of HTTP server development. With its modern architecture, universal compatibility, and modular design, Hattip empowers developers to build server applications that can run anywhere, from traditional server environments to cutting-edge serverless platforms. Whether you're a seasoned developer or just getting started with server-side JavaScript, Hattip provides the tools and capabilities you need to bring your ideas to life. So why wait? Join the Hattip revolution today and unleash the full potential of your server applications.


Hattip is made possible by the hard work and dedication of its creators and contributors. Special thanks to Fatih Aygün, Romuald Brillout, and all the contributors who have helped shape the project. Additionally, we would like to acknowledge the creators and contributors of third-party packages used in Hattip, including koajs/cors and GraphQL Yoga.

Ready to get started with Hattip? Check out the official documentation and start building universal server applications today!

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