How do you handle payment integrations in Laravel?

Payment integrations are one of the most carefully engineered parts of a fintech Laravel application. We use Laravel Cashier for Stripe and Paddle subscription billing, dedicated SDK integrations for direct payment APIs (Stripe Connect, Braintree, Adyen, Worldpay, Authorize.Net, Razorpay), webhook handlers with signature verification and replay protection, and idempotency middleware on all payment endpoints. Failed payments retry with exponential backoff, partial failures trigger compensation logic, and every payment event lands in a double-entry ledger with comprehensive audit trail. Webhook reception is decoupled from processing through queue jobs so payment provider retries do not cascade into double charges.