SabPaisa Payment Gateway for OpenCart — accept cards, UPI, net banking and wallets via SabPaisa. Hosted checkout out of the box, plus an optional native "Pay by UPI (scan QR)" flow rendered on your own store page. Includes an HMAC‑verified webhook receiver for reliable asynchronous UPI confirmation, an admin re‑check action to reconcile stuck orders, and an in‑admin refund console (full or partial refunds from the order page). All credentials are entered in the admin form — nothing hardcoded; the SabPaisa PHP SDK is bundled (no Composer). Supports OpenCart 3.0.x (PHP 7.3+) and 4.0.x (PHP 8.1+).