Typorithm · medium

Fastify

fastify-basicsnodejsfastifyperformanceplugins

Saved on this device

Full lesson · 8 learning steps Open any exercise for focused practice

Step 1 of 8 · intro card

Learn Fastify

Web Frameworks

Fastify is a fast, low-overhead Node framework: async handlers return the payload directly, logging is built in, a plugin system adds features, and JSON-schema validation and serialization make it quick. It is built for performance and developer experience.

Fastify is a high-performance Node framework focused on low overhead. You create an app with the Fastify() factory, optionally enabling its built-in logger.

Handlers are async functions that receive the request and simply return a value; Fastify serializes that return into the response, so there is no explicit res.json call.

Features are added through a first-class plugin system, and JSON-schema definitions drive both request validation and ultra-fast response serialization — the core reasons Fastify is quick.

Fastify() creates the app; logger: true enables logging.

Async handlers return the payload directly.

Plugins and JSON-schema serialization make it fast.

import Fastify from "fastify";
const app = Fastify({ logger: true });
app.get("/users/:id", async (req) => {
  return { id: req.params.id };
});
await app.listen({ port: 3000 });

Read the implementation

Connect each part of the code to the concept before you type.

1. Import Fastify

Fastify is a fast, low-overhead Node framework imported as a default factory.

import Fastify from "fastify";

2. Built-in logging

Passing logger: true turns on Fastify's built-in structured logger out of the box.

const app = Fastify({ logger: true });

3. Async handler

Fastify handlers are async functions that take the request and return the payload.

app.get("/users/:id", async (req) => {

4. Return the payload

Returning an object directly lets Fastify serialize it as the JSON response.

return { id: req.params.id };

5. Start listening

app.listen returns a promise, so it is awaited after all plugins are registered.

await app.listen({ port: 3000 });

A complete learning loop

Understand

Read the concept map and follow the code breakdown.

Reconstruct

Type the implementation, repair mistakes and work through every recall exercise.

Verify

Use the final check without hints; revisit weak concepts in short practice sessions.