Environment variables

Configuration that changes between environments (secrets, connection URLs, flags) belongs in environment variables, set on the app’s Environment tab.

Add or change a variable

1. Open the app → Environment.
2. Enter a name (DATABASE_URL, API_KEY, …) and its value, then Save Variable. Saving an existing name overwrites it.
3. Redeploy the app: variables are read at start, so changes only take effect on the next deployment or restart.

Variables are available to your app when it runs and to its build: there’s nothing to configure per variable.

Caution

Values are shown in plain text on the Environment tab to anyone with app access on your team: treat access to Apps as access to its secrets.

Removing

Deleting a variable takes effect the same way: on the next deployment or restart.