validity property
Validity duration of a key (in seconds). The key will automatically be removed after this time has expired. The default value of 0 never expires. Short-lived API keys are useful to grant temporary access to your data. For example, in mobile apps, you can't control when users update your app. So instead of encoding keys into your app as you would for a web app, you should dynamically fetch them from your mobile app's backend.
Implementation
@JsonKey(name: r'validity')
final int? validity;