Each subscription instance has a unique subscription ID, which you can obtain through webhooks or API requests. Use the following webhooks to track and manage new and existing subscription instances:

subscription.activated: A customer successfully purchased a subscription.
subscription.updated: You edited an active subscription in the app or with the API.
subscription.trial.reminder: A customer received a free trial reminder notification.
subscription.payment.reminder: A customer received a payment reminder notification.
subscription.charge.completed: FastSpring successfully rebilled a customer for their subscription.
subscription.charge.failed: A rebill transaction failed.
subscription.payment.overdue: A customer received an overdue payment notification.
subscription.canceled: You or a customer canceled an active subscription.
subscription.uncanceled: Remove a subscription cancelation.
subscription.deactivated: You or FastSpring deactivated a canceled subscription.

When Webhook Expansion is enabled, webhooks return the full subscription payload, consisting of all information related to that subscription instance. Otherwise, the webhook only returns the subscription ID.