Heroku with Express

Learn how to make Heroku, Express, and Dotenv Vault work together. This tutorial assumes you have already created a .env file and synced it.

You can find a complete example repo here.

Deploy to Heroku

Add a Procfile to run your Express app.

web: node index.js

Your index.js file should look something like this.

// index.js
const PORT = process.env.PORT || 5000
const express = require('express')
const app = express()

app.listen(PORT, () => {
  console.log(`Running on port ${PORT}.`)
})

app.get('/', (req, res) => {
  res.send(`Hello ${process.env.HELLO}`)
})

example

Commit that to code and push it to Heroku.

$ heroku create
$ git push heroku

Your app will say ‘Hello undefined’.

Nice. Next, let’s configure our environment variables using Dotenv Vault.

Require dotenv

Install dotenv.

$ npm install dotenv --save

Then require it as early as possible in your code.

// index.js
require('dotenv').config()
console.log(process.env) // for debugging purposes. remove when ready.

const PORT = process.env.PORT || 5000
const express = require('express')
const app = express()
...

example

Create your .env file

# .env
HELLO="Development"

Test it is working locally.

$ node index.js
{
  HELLO: 'Development'
}
Running on port 5000

It says Hello Development at http://localhost:5000.

Build .env.vault

First set a production value for when we deploy. I set it to HELLO=Production. Run dotenv-vault open to edit production values.

$ npx dotenv-vault open production

Then build your localized encrypted .env.vault file.

$ npx dotenv-vault build

Great! Commit your .env.vault file to code. It is safe and necessary to do so.

Set DOTENV_KEY

Lastly, set the DOTENV_KEY on Heroku.

Run npx dotenv-vault keys production to get your production decryption key.

$ npx dotenv-vault keys production
remote:   Listing .env.vault decryption keys... done

dotenv://:[email protected]/vault/.env.vault?environment=production

Visit your Heroku Project’s Environment Variables under settings of your heroku application and set it.

Commit and push

That’s it!

Commit those changes safely to code and deploy to Heroku.

When the app boots, it will recognize the DOTENV_KEY, decrypt the .env.vault file, and load the production environment variables to ENV. If a DOTENV_KEY is not set (like during development on your local machine) it will fall back to regular dotenv.

You’ll know things worked correctly if you see the message ‘Loading env from encrypted .env.vault’ in your heroku logs.