Environment Variables

Environment variables are how you give your app its configuration and secrets — API keys, connection strings, feature flags — without putting them in your code.

Adding a variable

1. Open your app and go to the Env Vars tab
2. Click Add Variable
3. Enter the name (for example STRIPE_SECRET_KEY) and the value
4. Save — your app restarts automatically, usually within 5–10 seconds

How they are protected

• Values are encrypted at rest
• Values are masked in the dashboard once saved, so they are not readable over your shoulder
• Variables are private to your app

System variables — set for you, and not editable

Some variables are managed by the platform:

You cannot change or delete these, and that is deliberate. If you try, you will see "Cannot modify system variable". This protects your app from losing its database connection — it is not a fault.

DATABASE_URL is re-applied on every deploy. If you overwrite it, your change will be replaced the next time you deploy.

Using an external database instead

If you want to connect to a database you host elsewhere, do not try to overwrite DATABASE_URL. Add your own variable under a different name — for example EXTERNAL_DATABASE_URL — and read that in your code.

Your app must read the port from the environment

// Node.js
const port = process.env.PORT || 3000;
app.listen(port, '0.0.0.0');

# Python
port = int(os.environ.get('PORT', 5000))
app.run(host='0.0.0.0', port=port)

Bind to 0.0.0.0, never localhost — an app listening on localhost cannot be reached from outside its container.

Good practice

• Never commit secrets to git — use variables instead
• Use clear names: STRIPE_SECRET_KEY, not KEY1
• Names are case-sensitive: DATABASE_URL is not the same as database_url
• Watch for trailing spaces in pasted values

Setting several at once

You can set multiple variables in one request from your terminal:

curl -X POST https://<your panel address>/api/client/paas/{appId}/env \
  -H "Content-Type: application/json" \
  -d '{"vars": {"KEY1": "value1", "KEY2": "value2"}}'

If a variable does not seem to apply

• Confirm it is listed in the Env Vars tab
• Check the spelling and capitalisation
• Your app restarts automatically after a change — check the Logs tab to confirm it restarted cleanly