Environment variables

Why use environment variables?

Hardcoding secrets (API keys, database URLs, passwords) in your code is a security risk. Environment variables keep secrets out of your source code and let you use different values in development vs production.

Setting variables

1.Open your project in the editor.

2.Click the gear icon (Settings) in the toolbar.

3.Select Environment.

4.Add key-value pairs and click Save.

Variables are encrypted at rest and injected into your container at startup.

Accessing variables in code

Node.js / JavaScript:

const apiKey = process.env.MY_API_KEY
const dbUrl  = process.env.DATABASE_URL

Python:

import os
api_key = os.environ.get('MY_API_KEY')
db_url  = os.environ.get('DATABASE_URL')

Next.js (public, browser-accessible):

// Must be prefixed with NEXT_PUBLIC_
const apiUrl = process.env.NEXT_PUBLIC_API_URL

Changes take effect

Changes to environment variables require a container restart to take effect. Click Restart Container in the toolbar after saving, or stop and start your process in the terminal.

.env files

You can also create a .env file in your project root and use dotenv:

npm install dotenv

require('dotenv').config()
console.log(process.env.MY_KEY)

Never commit .env files. Add .env to your .gitignore and use the Settings panel for secrets that need to survive across container restarts.