# How to deploy an Express app to Platformatic Cloud

If you have an existing [Express](http://expressjs.com/?utm_campaign=Blog%20post%20-%20How%20to%20deploy%20an%20Express%20app%20to%20Platformatic%20Cloud&utm_medium=blog&utm_source=Platformatic%20Blog) application, migrating it to [Fastify](https://www.fastify.io/?utm_campaign=Blog%20post%20-%20How%20to%20deploy%20an%20Express%20app%20to%20Platformatic%20Cloud&utm_medium=blog&utm_source=Platformatic%20Blog) to benefit from its speed and simplicity might be a time-consuming task that you can't immediately prioritize. You can however still take advantage of Fastify's flexibility, as well as Platformatic’s [open-source backend tools](https://oss.platformatic.dev/?utm_campaign=Blog%20post%20-%20How%20to%20deploy%20an%20Express%20app%20to%20Platformatic%20Cloud&utm_medium=blog&utm_source=Platformatic%20Blog) and [Cloud hosting service](https://platformatic.cloud/?utm_campaign=Blog%20post%20-%20How%20to%20deploy%20an%20Express%20app%20to%20Platformatic%20Cloud&utm_medium=blog&utm_source=Platformatic%20Blog).

We’ve designed [Platformatic Cloud](https://platformatic.cloud/?utm_campaign=Blog%20post%20-%20How%20to%20deploy%20an%20Express%20app%20to%20Platformatic%20Cloud&utm_medium=blog&utm_source=Platformatic%20Blog) to deliver the best deployment and hosting experience for Node.js apps. It's built on top of the modern [Fastify](https://www.fastify.io/?utm_campaign=Blog%20post%20-%20How%20to%20deploy%20an%20Express%20app%20to%20Platformatic%20Cloud&utm_medium=blog&utm_source=Platformatic%20Blog) web framework, which provides logging, request validation and a powerful plugin system out-of-the-box, as well as [incredible](https://www.fastify.io/benchmarks/?utm_campaign=Blog%20post%20-%20How%20to%20deploy%20an%20Express%20app%20to%20Platformatic%20Cloud&utm_medium=blog&utm_source=Platformatic%20Blog) [performance.](http://performance.In)

In this guide, you'll learn how to use the [@fastify/express](https://www.npmjs.com/package/@fastify/express?utm_campaign=Blog%20post%20-%20How%20to%20deploy%20an%20Express%20app%20to%20Platformatic%20Cloud&utm_medium=blog&utm_source=Platformatic%20Blog) plugin to help you rapidly migrate your existing Express application to use Platformatic Service, and then deploy it to Platformatic Cloud.

*This guide assumes that you have some experience building applications with the* [*Express*](https://expressjs.com/?utm_campaign=Blog%20post%20-%20How%20to%20deploy%20an%20Express%20app%20to%20Platformatic%20Cloud&utm_medium=blog&utm_source=Platformatic%20Blog) *framework.*

## Example Express application

For the purpose of this guide, we have a basic example Express application. Although this app has a specific structure, the migration steps covered in this guide can generally be applied to any Express application.

> The code for the example Express and migrated Platformatic Service applications is available [on GitHub](https://github.com/platformatic/examples/tree/main/applications/deploy-express-app-platformatic-cloud?utm_campaign=Blog%20post%20-%20How%20to%20deploy%20an%20Express%20app%20to%20Platformatic%20Cloud&utm_medium=blog&utm_source=Platformatic%20Blog).

Here's the structure of the example Express application:

```plaintext
├── app.js
├── package.json
├── routes
│   └── users.js
└── server.js
```

It has the following dependencies:

```json
// package.json

"dependencies": {
  "express": "^4.18.2"
}
```

The application has routes in `routes/users.js`:

```javascript
// routes/users.js

import express from 'express'

const router = express.Router()

router.use(express.json())

router.post('/', function createUser(request, response, next) {
  const newUser = request.body

  if (!newUser) {
    return next(new Error('Error creating user'))
  }

  response.status(201).json(newUser)
})

router.get('/:user_id', function getUser(request, response, next) {
  const user = {
    id: Number(request.params.user_id),
    first_name: 'Bobo',
    last_name: 'Oso'
  }

  response.json(user)
})

export const usersRoutes = router
```

In `app.js`, we have a factory function that creates a new Express server instance and mounts the routes:

```javascript
// app.js

import express from 'express'

import { usersRoutes } from './routes/users.js'

export default function buildApp() {
  const app = express()

  app.use('/users', usersRoutes)

  return app
}
```

And in `server.js` we're calling the factory function and starting the server listening for HTTP requests:

```javascript
// server.js

import buildApp from './app.js'

const express = buildApp()

express.listen(3042, () => {
  console.log('Example app listening at http://localhost:3042')
})
```

> The routes in your Express application should be mounted on an Express router (or multiple routers if needed). This will allow them to be mounted using `@fastify/express` when you migrate your app to Platformatic Service.

## Creating a new Platformatic Service app

To migrate your Express app to Platformatic Service, create a new Platformatic Service app with:

```bash
npm create platformatic@latest
```

Be sure to select `Service` as the project type. You should also say `yes` when you're asked if you want to create the GitHub Actions workflows for deploying your application to Platformatic Cloud.

Once the project has been created, you can delete the example `plugins` and `routes` directories.

### Using ES modules

If you're using ES modules in the Express application code that you'll be migrating, ensure that there's a `type` field in `package.json` set to `module`:

```bash
npm pkg set type=module
```

## Migrate the Express routes

Copy over the `routes` directory from your Express app.

### Install @fastify/express

Install the [`@fastify/express`](https://www.npmjs.com/package/@fastify/express?utm_campaign=Blog%20post%20-%20How%20to%20deploy%20an%20Express%20app%20to%20Platformatic%20Cloud&utm_medium=blog&utm_source=Platformatic%20Blog) Fastify plugin to add full Express compability to your Platformatic Service app:

```bash
npm install @fastify/express
```

### Mounting the Express routes

Create a root Fastify plugin that register's the `@fastify/express` plugin and loads your Express routes:

```javascript
// root-plugin.js

import { usersRoutes } from './routes/users.js'

/** @param {import('fastify').FastifyInstance} app */
export default async function (app) {
  await app.register(import('@fastify/express'))

  app.use('/users', usersRoutes)
}
```

### Configuring the Platformatic Service app

Edit your app's `platformatic.service.json` to load your root plugin:

```json
// platformatic.service.json

{
  ...,
  "plugins": {
    "paths": [{
      "path": "./root-plugin.js",
      "encapsulate": false
    }],
    "hotReload": false
  },
  "watch": false
}
```

These settings are important when using `@fastify/express` in a Platformatic Service app:

* `encapsulate` — You'll need to disable encapsulation for any Fastify plugin which mounts Express routes. This is due to the way that `@fastify/express` works.
    
* `hotReload` and `watch` — You'll need to disable hot reloading and watching for your app, as they don't currently work when using `@fastify/express`. This is a known issue that we're working to fix.
    

## Deploying to Platformatic Cloud

![Screenshot of an app on Platformatic Cloud](https://cdn.hashnode.com/res/hashnode/image/upload/v1684821077691/d0e8bd11-bbdf-4c62-a961-f265f8f01bf8.png align="left")

Once you've migrated your Express app to Platformatic Service, you're ready to deploy it to Platformatic Cloud:

1. Create a new repository on GitHub, then commit and push up the code for your Platformatic Service app.
    
2. Follow our [Cloud Quick Start Guide](https://docs.platformatic.cloud/docs/quick-start-guide/?utm_campaign=Blog%20post%20-%20How%20to%20deploy%20an%20Express%20app%20to%20Platformatic%20Cloud&utm_medium=blog&utm_source=Platformatic%20Blog) to configure the deployment for your Platformatic Service app. You can skip the steps for creating a GitHub repository and creating a new Platformatic app.
    

## Wrapping up

You can learn more about building Node.js apps with Platformatic service in the [Platformatic Service](https://oss.platformatic.dev/docs/reference/service/introduction?utm_campaign=Blog%20post%20-%20How%20to%20deploy%20an%20Express%20app%20to%20Platformatic%20Cloud&utm_medium=blog&utm_source=Platformatic%20Blog) documentation.

Once you've migrated your Express app to use Platformatic Service with `@fastify/express`, you might then want to consider fully migrating your Express routes and application code to Fastify. This tutorial shows how you can approach that migration process: [How to migrate your app from Express to Fastify](https://simonplend.com/how-to-migrate-your-app-from-express-to-fastify/?utm_campaign=Blog%20post%20-%20How%20to%20deploy%20an%20Express%20app%20to%20Platformatic%20Cloud&utm_medium=blog&utm_source=Platformatic%20Blog) ([video](https://simonplend.com/learning-fastify-how-to-migrate-your-app-from-express-to-fastify/?utm_campaign=Blog%20post%20-%20How%20to%20deploy%20an%20Express%20app%20to%20Platformatic%20Cloud&utm_medium=blog&utm_source=Platformatic%20Blog)).