Lesson 3 / 30

Your First Server

Q: Why does Fastify use async/await?

To handle I/O operations cleanly and maintain performance. Fastify is built on async/await to handle asynchronous operations efficiently and keep the non-blocking event loop clean.

A running Fastify server in under ten lines.

Hello, World!

Create an instance, define one route, and start the server. Notice the async nature—Fastify is async-first.

import Fastify from 'fastify';

const fastify = Fastify();

fastify.get('/', async (request, reply) => {
  return { message: 'Hello, World!' };
});

await fastify.listen({ port: 3000 });
console.log('Server running on http://localhost:3000');

Output:

Server running on http://localhost:3000

The Fastify instance

Fastify() creates the server instance. fastify.get(route, handler) registers a GET route. await fastify.listen() starts the HTTP server with graceful shutdown support.

Quick check: Why does Fastify use async/await?

It's required by Node.js
To handle I/O operations cleanly and maintain performance
Callbacks are deprecated

Answer

To handle I/O operations cleanly and maintain performance — Fastify is built on async/await to handle asynchronous operations efficiently and keep the non-blocking event loop clean.