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Environment variables

Configure application values and secrets in project settings.

Set application variables

Open Settings → Environment in your project. Choose a plain value or a secret. Variable names use letters, numbers and underscores and cannot begin with a number. Platform-reserved names cannot be overridden.

Plain values are visible in settings. Secret values are encrypted in storage and are not returned as plaintext by the settings API. Keep credentials out of your repository.

Apply changes with a deployment

Deployment configuration is frozen when a deployment is admitted. Editing project variables does not rewrite a running deployment; create a new deployment to apply changes.

Attached managed resources supply DATABASE_URL or REDIS_URL to deployments. Avoid conflicting project variables with these managed connection keys. PORT is controlled by the configured application port.