UPI with PhonePe for Multi-Business Apps: Spring Boot + React Native

If your app serves multiple businesses, UPI needs careful routing. Here’s how we wired PhonePe so each business gets paid to its own merchant account.

Data Model

• Business: PhonePe merchant keys, UPI ID, callback URLs, settlement preferences.
• Payment: status machine (created → pending → success/failed → reconciled), amount, currency, external reference IDs.
• Audit: request/response logs (masked), signatures, retries.

Flow

1. Client requests payment intent with business ID and amount.
2. Backend signs the request with the business’s merchant key; creates a Payment record.
3. Client shows QR/Intent; user pays via any UPI app.
4. PhonePe calls your callback → verify signature → update status.
5. Nightly reconciliation: cross-check settlements and mark reconciled.

Security & Reliability

• HMAC signatures on every message; validate timestamps/nonces.
• Idempotent callbacks (dedupe by transaction reference).
• Retries with back-off for transient failures.
• Mask PII; store only what you must (no sensitive PAN-like data).

Client UX

• Show a countdown on the UPI screen with “I’ve paid” and “Try again” actions.
• Deep-link to installed UPI apps; fallback to static QR.
• Clear success/failure screens; auto-dismiss on success callback.

With the right abstractions, you can support thousands of payments across many businesses without mixing funds.