Using environment variables (env vars/.env file) with Routing Controllers

Table of contents

This is a guide to setting up Routing Controllers (a very simple npm package to run an express server) with MongoDB.

I have a guide on setting up routing-controllers from scratch here.

If you have now set up your Routing Controllers application, you probably now need to configure it with environment variables (e.g. to connect to a database).

An easy way to set this up with with dotenv.

First install dotenv as a dependency

Install dotenv (yarn add dotenv) to your package.json

Create a .env file

For local development you will probably want to use .env file.

First: add it to your gitignore:

# in your .gitignore file

And then create a file in your root directory called .env, with some environment variables. In this case we are going to define a port number to use:


Load your env vars

In your routing-controllers server setup file, add this:

import 'dotenv/config' // << just add this
if you are doing cjs import with require() then it should be this:


const PORT = process.env.ROUTING_CONTROLLERS_PORT || 4000;`Starting server on http://localhost:${PORT}`);

Use it on production

In your production app you shouldn't use .env files, but proper environment variables. You can set these up in your normal way (depending on how you are hosting your app) and dotenv will pick them up.

Read more about dotenv

Before you use this on a real application I'd recommend you read the documentation for dotenv as there are lots of features you should be aware of.

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