Fastify

Fastify is a high-performance Node.js framework with a plugin-oriented design. It is a good choice when you want fast request handling and a structured way to register route groups.

Choose Fastify When

• Performance matters
• You like plugin-style route registration
• You want built-in structured logging support
• You want a framework that ships its own TypeScript types

Generated Entry Point

Fastify projects generate a src/server.ts file that creates the app, registers optional features, mounts routes, and starts the server.

src/
  server.ts
  routes/ or modules/
  config/
  shared/

Route Example

import type { FastifyInstance } from "fastify";
import { UsersController } from "./users.controller";

export async function usersRoutes(app: FastifyInstance) {
  app.get("/", UsersController.getAll);
  app.post("/", UsersController.create);
  app.get("/:id", UsersController.getById);
  app.patch("/:id", UsersController.update);
  app.delete("/:id", UsersController.remove);
}

The server registers the route group with a prefix:

app.register(usersRoutes, { prefix: "/api/v1/users" });

Request Flow

request
  |
  v
Fastify app
  |
  v
registered route plugin
  |
  v
controller
  |
  v
optional service/repository

Optional Features

Architecture Notes

• Minimal Fastify projects use route files with inline handlers.
• Modular Fastify projects use src/modules/{feature}.
• Layered Fastify projects use top-level route, controller, service, repository, interface, and validator folders.