A field guide to instant payments: Pix, UPI and their neighbours

In Brazil and India, the most common way to pay online is no longer a card. It is an instant bank transfer started from a phone: Pix in Brazil, UPI in India. Similar systems run in Thailand, Singapore, Poland and elsewhere.

If you sell into these markets, you will want to offer them. This guide explains how they work, how they differ from cards, and what changes in your integration.

Figures in this post are illustrative placeholders, not measured results.

How an instant payment works

The flows differ in detail but share a shape:

1. You create a payment request for a fixed amount.
2. The shopper sees a QR code on desktop, or is sent to their banking or payments app on mobile.
3. The shopper approves the payment in that app, usually with a PIN or biometric check.
4. Funds move from the shopper's bank account to the collecting account within seconds.
5. You receive a confirmation and fulfil the order.

There is no card number, no expiry date and no 3-D Secure step. Authentication happens inside the shopper's own app.

Pix in Brazil

Pix is run by Brazil's central bank and is available every day of the year. For online checkout, the common flow is a dynamic QR code or a copy-and-paste code that encodes the amount and an expiry time.

Things to know:

• Expiry matters. Set a sensible window, often 15 to 60 minutes. A shopper who leaves to find their phone should still be able to pay when they return.
• Refunds are pushed. You send money back to the payer's account. There is no chargeback process in the card sense, though a special return mechanism exists for fraud and operational errors.
• Pix installments. Newer variants support paying over time, but availability varies by bank. Many shoppers still expect card installments for larger purchases, so offer both.

UPI in India

UPI links a bank account to a virtual payment address and runs through a range of consumer apps. Online, it typically appears as a QR code on desktop or an intent link that opens the shopper's chosen app on mobile.

Things to know:

• Collect requests are being phased down in favour of intent and QR flows in many contexts. Build for intent and QR first.
• Per-transaction limits apply. Limits vary by use case and bank. Large tickets may need another method.
• Recurring payments are supported through mandates, with rules on pre-debit notification.

How these differ from cards

The last row matters most for conversion. A card payment fails loudly with a decline code. An instant payment usually fails quietly: the shopper never approves it, and the request expires.

What changes in your integration

Treat payment as asynchronous. Your order is not paid when the shopper sees the QR code. It is paid when you receive the confirmation webhook. Show a waiting state, poll from your own server only if you must, and rely on the webhook as the source of truth.

Design the waiting screen. On desktop, show the QR code large, a countdown and a copy-code button. On mobile, open the app directly and handle the shopper returning to your page.

Handle expiry cleanly. When a request expires, offer a new one in one tap rather than sending the shopper back to the start.

Reconcile by reference. Each payment carries a reference you set. Use your order ID so reconciliation does not depend on matching amounts.

Plan refunds. Because refunds are outbound transfers, check how your provider handles partial refunds and what happens if the shopper's account has closed.

With International Orders, Pix and UPI are available through the same Unified Orders API and Checkout Components as cards. The order moves to paid when the confirmation arrives, and the same webhook events fire.

Their neighbours

Several other markets run comparable systems. A few you are likely to meet:

• PromptPay in Thailand
• PayNow in Singapore
• BLIK in Poland, which uses a six-digit code from the banking app
• SPEI in Mexico, a bank transfer rail often used for higher-value orders

The integration pattern above applies to all of them with small differences in expiry, limits and refund handling.

Where to start

Look at your traffic by country. If more than a small share comes from a market where an instant method leads, offering it is usually the single largest conversion change you can make there. The payment methods catalogue lists each method's markets, currencies and refund support, and you can try them in the sandbox by following getting started.