Configure Chargebee Smart Dunning with custom retry settings and handle dunning webhooks

Steps

1. Enable Smart Dunning in the Chargebee dashboard under Settings > Billing > Dunning; Smart Dunning supports up to 12 automatic retries with Chargebee determining optimal retry timing based on decline type
2. Classify retries by decline type: hard declines (e.g., do_not_honor) are not retried until a payment method update occurs; soft declines are retried automatically on a Chargebee-managed schedule
3. Register a webhook for payment_failed event; the payload includes invoice_id, next_retry_at, dunning_status, and failure_reason_code
4. Register a webhook for subscription_changed event which fires when a subscription's status changes to dunning or active after recovery
5. At the end of the dunning cycle, handle the subscription_cancelled or subscription_changed webhook (depending on your configured end-of-dunning action) to suspend entitlements
6. Use POST /api/v2/invoices/INVOICE_ID/collect_payment to manually trigger a payment retry outside of Smart Dunning when a customer updates their card