# Express Server

Express is a minimal and flexible Node.js web application framework that provides a robust set of features for web and mobile applications.

With a myriad of HTTP utility methods and middleware at your disposal, creating a robust API is quick and easy.

#### **👉Prerequisites** : Node, npm

#### **👉 Steps**:

1. `npm init` in the root folder. Fill up the details and it will generate a package.json for you. You may change the entry point to server.js, optional. Create a folder "backend" and inside it a file "server.js"
    
2. Edit the package.json file and add in the scripts object, the following:  
    `"start": "node backend/server.js", "server": "nodemon backend/server.js"`
    
3. Install the dependencies:  
    `npm i express dotenv`  
    `npm i -D nodemon` -D implies that it is a devDependency.
    

#### **👉Lets Edit the server.js file now to spin up a server.**

[![nodejs code for express server](https://res.cloudinary.com/practicaldev/image/fetch/s--PB14Tb96--/c_limit%2Cf_auto%2Cfl_progressive%2Cq_auto%2Cw_880/https://dev-to-uploads.s3.amazonaws.com/uploads/articles/rs9knb7m8bjfchxnifyp.png align="left")](https://res.cloudinary.com/practicaldev/image/fetch/s--PB14Tb96--/c_limit%2Cf_auto%2Cfl_progressive%2Cq_auto%2Cw_880/https://dev-to-uploads.s3.amazonaws.com/uploads/articles/rs9knb7m8bjfchxnifyp.png)

* Bring in express and other stuff by requiring it at the top.
    
* dotenv is used so that we can use Environment variables.
    
* Specify the `PORT=5000` in a .env file, that way we can acces it in the code like `process.env.PORT`
    
* Make a instance of express, using its constructor and assign it to app
    
* Call the listen method on app object and pass in the port and the callback
    

Now, you can fire it up by running the command `npm run server`, this way nodemon will watch our files for changes and server will be up and running.