Build Super Fast APIs with Fastify

Fastify is a Node.js framework that focuses on providing exceptional performance when building web applications, especially APIs.

It offers a range of features that allow us to develop scalable and fast applications, with minimal overhead and an intuitive structure.

Among the standout features of Fastify are:

• High-level performance: Fastify is designed to handle a large number of requests per second with efficient resource usage.
• Easy routing: Allows for simple and clear route definitions.
• Plugin support: Facilitates the integration of additional functionalities through an extensible plugin system.
• Efficient error handling: Provides mechanisms for effectively and customarily managing errors.
• Data optimization and validation: Includes tools for validating and optimizing request data.

For more details and documentation on Fastify, we can visit the official repository at GitHub - fastify/fastify. Here we will find additional examples and complete documentation.

How to Install Fastify

To start using Fastify, we need to install it in our Node.js project. We can easily do this using npm, the Node.js package manager. Make sure we have Node.js and npm installed, and then run the following command to add Fastify to our project:

npm install fastify

This command will download and install the Fastify library in our node_modules directory and add it to the dependencies in our package.json file.

How to Use Fastify

Once we have installed Fastify, we can start using it to build our API. Next, we will see how to create a basic server, define routes, and handle requests using Fastify.

Creating a Basic Server

First, let’s create a file named server.mjs in our project. In this file, we will set up a basic server using Fastify:

import Fastify from 'fastify'

const fastify = Fastify({
  logger: true
})

// Example GET route
fastify.get('/hello', async (request, reply) => {
  reply.type('application/json').code(200)
  return { hello: 'world' }
})

// Example POST route
fastify.post('/echo', async (request, reply) => {
    return request.body;
});

fastify.listen({ port: 5000 }, (err, address) => {
  if (err) throw err
  // Server is now listening on ${address}
})

In this code:

• We use Fastify to create an instance of the Fastify server with logging support.
• We define two routes: a GET route at /hello that returns a simple greeting and a POST route at /echo that returns the content sent in the request.
• Finally, we start the server on port 3000 and log a message to the console to confirm that it is running.

Error Handling

Fastify offers a robust system for handling errors. We can capture global errors and customize error responses. Here is an example of how to define a global error handler:

fastify.setErrorHandler((error, request, reply) => {
    fastify.log.error(error);
    reply.status(500).send({ error: 'Internal Server Error' });
});

In this example, we are capturing all unhandled errors and responding with a generic error message and a status code of 500.

Using Plugins

Fastify has a plugin system that allows us to extend the framework’s functionality. We can add plugins to handle data validation, authentication, and much more. For example, to add a plugin that validates request bodies, we could do the following:

const Fastify = require('fastify');
const fastify = Fastify({ logger: true });

// Plugin for data validation
fastify.register(require('fastify-schema-validation'), {
    // Plugin configuration
});

// POST route with data validation
fastify.post('/register', {
    schema: {
        body: {
            type: 'object',
            required: ['username', 'password'],
            properties: {
                username: { type: 'string' },
                password: { type: 'string' }
            }
        }
    }
}, async (request, reply) => {
    return { message: 'User registered successfully' };
});

In this example, we register a schema validation plugin and define a POST route that validates the request body according to a JSON schema.