Creating a High-Performance REST API With Fastify and PostgreSQL

When building scalable back-end services in Node.js, Fastify offers blazing-fast HTTP performance with a developer-friendly interface. In this guide, we’ll build a simple REST API connected to a PostgreSQL database using pg.

Why Fastify?

Fastify is a modern web framework for Node.js that prioritizes performance and low overhead. It supports JSON Schema validation, automatic Swagger documentation, hooks, and more.

Step 1: Initialize Your Project

npm init -y
npm install fastify pg fastify-plugin

Step 2: Set Up Fastify and Register the Database

// db.js
const fp = require('fastify-plugin');
const { Pool } = require('pg');

async function dbConnector(fastify, options) {
  const pool = new Pool({
    user: 'postgres',
    host: 'localhost',
    database: 'fastifydb',
    password: 'password',
    port: 5432,
  });

  fastify.decorate('pg', pool);
}

module.exports = fp(dbConnector);

Step 3: Define the API Routes

// routes/user.js
async function userRoutes(fastify, options) {
  fastify.get('/users', async (request, reply) => {
    const result = await fastify.pg.query('SELECT * FROM users');
    return result.rows;
  });

  fastify.post('/users', async (request, reply) => {
    const { name, email } = request.body;
    const result = await fastify.pg.query(
      'INSERT INTO users (name, email) VALUES ($1, $2) RETURNING *',
      [name, email]
    );
    return result.rows[0];
  });
}

module.exports = userRoutes;

Step 4: Start the Server

// index.js
const fastify = require('fastify')({ logger: true });
const dbConnector = require('./db');
const userRoutes = require('./routes/user');

fastify.register(dbConnector);
fastify.register(userRoutes);

const start = async () => {
  try {
    await fastify.listen({ port: 3000 });
  } catch (err) {
    fastify.log.error(err);
    process.exit(1);
  }
};

start();

Step 5: Test Your API

Make sure PostgreSQL is running and a users table exists. You can now test endpoints using tools like Postman or cURL:

curl http://localhost:3000/users

Conclusion

Fastify is a fantastic choice for building REST APIs in Node.js when speed and scalability are critical. Pairing it with PostgreSQL provides a powerful, production-ready backend stack.

Now check out - Phoenix LiveView: The Pro’s Guide to Scalable Interfaces and UI Patterns. Whether you’re building collaborative apps, integrating APIs, or orchestrating systems across multiple languages, this guide will help you use Phoenix as the real-time command center your architecture deserves.