===How to run/work with development mode for NodeJS Apps===

**Step 1 :** Log into N99panel. From under N99panel dashboard, click 'Node Apps'

{{:nodejs:click-node-apps.png?direct&400|}}
\\

**Step 2 :** Now click 'Link a Node App

{{:nodejs:link-node-app.png?direct&400|}}
\\

**Step 3 :** Fill in the form as under

{{:nodejs:dev-form-2.png?direct&400|}}

**Important point :**\\
  - Select the VHost (website) mentioned along with the user and the port range.\\ 
  - Enter the ‘App Web path’ . This would be like /app1 or /app2 or it can even be the website root i.e. /\\
  - Enter the ‘App Port’ . The port entered under should be within the range of the port numbers mentioned in point 1.\\
  - Select the ‘App Mode’. This should be ‘Development’\\

With the above steps, you have mapped the web-server to the VHost/Website’s URL part and the port number where we can expect the NodeJS App to be running.

Read further on how to start the App when logged into SSH

--------------------------------------------------------------

N99panel comes with multiple NodeJS versions i.e. 10, 12, 14, 16, 18, 20. These versions can be referenced from within SSH using the commands 
<code>
node10
node12
node14
node16
node18
node20
</code> 
respectively. The npm’s accompanying these versions can be referenced via 
<code>
npm10
npm12
npm14
npm16
npm18
npm20
</code>
respectively. The default node command refers to node18. Please refer to this article to change the default version of node CLI - [[:nodejs:cli-version|How to change the default version of node or NodeJS CLI for a user]]\\


Now to run the App,

Login into the server/VPS via SSH of the user ID under which the VHost/website is running.
Though you can run the NodeJS App from any folder, but ideally create a new App folder within the node_apps folder. This would help later also when we shift this App to the Production mode.

Now assuming that you created a app folder app1 , now under that folder upload all your source files including package.json . Lets’s say that we wish to user version 16 , to run NPM commands w.r.t. that ideally we will use npm16  .

To run the app, we should first ensure that the NodeJS source file creates the Node server at the ‘App Port’ number as specified earlier. We’ll explain further via example
Let’s say the user port range is 50051 to 50060 , and the port we entered under ‘App Port’ is 50051
Now my app file is say app.js . In my app.js I would need to create the server on port 50051 .
To now actually run the app, we just need to type

<code>
node16 app.js
</code>  

Above process would now start the App as a foreground process

To start the App as a background process, do the following

<code>
node16 app.js &
</code>  

If there are errors, it will simply show the errors and the process would end. And when you fix the errors, you can again try starting the App.

When you believe that you app is running stably and as per your expectations, at that moment you can decide to shift your App to the Production mode. Click here to read about it.