How do you handle COD (Cash on Delivery) in Magento?

COD is still ~30-40% of Indian e-comm orders. Three concerns to wire:

1. Pincode whitelisting — serviceable pincodes via Delhivery / Shiprocket / Bluedart APIs, with COD-eligible flags per pincode (some are prepaid-only).
2. RTO mitigation — Return-to-Origin rate on COD is 15-25% in India. We add: OTP verification before checkout, partial-prepayment options (₹1 token), and risk scoring (block COD for > 10 RTOs).
3. Reconciliation — courier-COD remittance vs Magento order status, automated via Shiprocket / Pickrr APIs into Tally / Zoho.