How to integrate UPI payment gateway in a website?

When UPI caps are hit mid-checkout, the software should recommend debit/credit cards, net banking, and wallets as immediate fallback options.

It should also suggest bank transfer (IMPS/NEFT/RTGS) for high-value hospital bills.

The fallback choices must appear instantly with a clear reason for the UPI failure for user transparency

The accounting package should query the mapped hospital category and current RBI/NPCI limit table in real time at payment initiation.

If eligible for higher limits, it should display a dynamic in-app and checkout banner message confirming the enhanced cap.

This message must be API-driven and audit-logged to ensure regulatory traceability.

Use idempotency keys plus a strict retry cap (e.g., max 3 retries on timeouts/5xx only) so duplicate hospital debits can’t occur.

Apply exponential backoff with jitter + a circuit breaker that opens on high latency/error rates and routes retries into a delayed queue.

Enforce per-hospital and global concurrency limits, queuing excess requests with a short TTL tied to the original invoice/mandate.

Log every retry decision and expose metrics/alerts (retry count, success-after-retry, circuit state) so ops can tune thresholds safely.

Use idempotency keys + a strict retry cap (e.g., max 3 retries on timeouts/5xx only) so duplicate UPI debits can’t occur.

Apply exponential backoff with jitter and a circuit breaker that opens on high latency/error rates, pushing retries to a delayed queue.

Enforce per-hospital and global concurrency limits, queuing excess requests with a short TTL and linking them to the original txn.

Log every retry decision and expose metrics/alerts (retry count, latency, circuit state) so ops can safely tune thresholds.

Enable a daily aggregate cap alert when hospital-bill UPI receipts approach the category’s ₹10L per-day limit.

Add a high-value transaction alert for bills nearing the ₹5L per-transaction cap.

Use an unmapped-purpose/MCC alert to flag hospital payments missing the correct healthcare code.

Enable a settlement mismatch alert when UPI collections don’t reconcile with hospital invoices or gateway settlements.