PromptPay QR Payment Integration for Websites: 3 Ways to Do It

Three Ways to Take PromptPay on a Website

You can accept PromptPay on a website in three ways: (1) a static QR with manual slip checks, (2) a dynamic QR from a payment gateway that confirms automatically by webhook, or (3) a QR payment API directly from a Thai bank. Which is right depends on how many payments you take a day and whether a person can check each one.

PromptPay is how Thai customers prefer to pay online — scan, confirm in their banking app, done. Whether you run a shop, take clinic deposits or collect restaurant pre-orders, missing PromptPay costs conversions at exactly the moment the customer is ready to pay.

Option 1: Static PromptPay QR + Slip Check

You generate a PromptPay QR for your business's PromptPay ID (phone number, tax ID or e-wallet ID) with the order amount, show it at checkout, and ask the customer to send the slip.

Generating the QR yourself. A PromptPay QR is a Thai QR Code payload (EMVCo format) that encodes the PromptPay ID and, optionally, the amount. Open-source libraries generate the payload; you render it as a QR image:

import generatePayload from "promptpay-qr"; // npm: promptpay-qr
import QRCode from "qrcode";

const payload = generatePayload("0812345678", { amount: 450.0 });
const dataUrl = await QRCode.toDataURL(payload);
// <img src={dataUrl} alt="PromptPay QR for ฿450" />

Pros: no gateway, no per-transaction fee, set up in a day.

Cons: nothing confirms the payment automatically. Staff must match every slip to the bank statement, and fake or reused slips are a real problem. It works for a handful of orders a day; it does not scale.

Slip-verification services exist that read the QR on a transfer slip and check it with the bank. They reduce fraud but still depend on the customer sending the slip.

Option 2: Dynamic QR Through a Payment Gateway (Recommended Default)

A gateway such as Omise (Opn Payments) or 2C2P creates a one-time QR for each charge. When the customer pays, the gateway calls your webhook and your system marks the order paid — no slip, no human check.

// Server: create a PromptPay charge (Omise example; amount in satang)
const charge = await omise.charges.create({
  amount: 45000, // ฿450.00
  currency: "thb",
  source: { type: "promptpay" },
  metadata: { orderId },
});
const qrImage = charge.source.scannable_code.image.download_uri;

// Webhook: the gateway tells you the charge succeeded
export async function POST(req: Request) {
  const event = await req.json();
  // Verify authenticity per your gateway's docs (signature, or re-fetch the
  // charge by ID with your secret key) before trusting the payload.
  const charge = await omise.charges.retrieve(event.data.id);
  if (charge.status === "successful") {
    await markOrderPaid(charge.metadata.orderId); // must be idempotent
  }
  return new Response("OK");
}

Pros: automatic confirmation, a reference per order, cards and wallets in the same integration, and a dashboard for refunds.

Cons: a per-transaction fee and merchant onboarding (KYC). Compare current fees with each provider — they change and can be negotiable at volume.

Two rules that prevent most payment bugs:

• The webhook is the source of truth, not the customer's screen. People close the tab right after scanning.
• Make the handler idempotent. Gateways retry webhooks; a second "successful" event must not double-ship an order or double-book a slot.

Option 3: Bank QR Payment APIs

Major Thai banks offer QR payment and payment-notification APIs to merchants with an agreement. They can be cheaper per transaction at high volume, but onboarding is slower, documentation is often Thai-first, and you usually integrate one bank at a time. They suit businesses already doing high monthly volume, not a new site.

Which Should You Choose?

• A few orders a day, a staff member watching LINE: static QR + slip check is fine to start.
• Anything automated — bookings with deposits, online ordering, e-commerce: a gateway with webhooks.
• High, steady volume and an existing banking relationship: evaluate the bank's own API.

PromptPay Inside LINE

For booking deposits and restaurant pre-orders taken through a LINE LIFF app, the flow is: create the booking as pending, show the dynamic QR in the LIFF screen, and let the webhook confirm the booking and push the LINE confirmation. On a phone, offer a "Save QR" button too — many customers pay by saving the image and opening it in their banking app on the same device.

Before You Go Live

• Apply for the merchant account early — KYC, not code, usually sets the launch date.
• Test in sandbox: success, failure, expiry of the QR, duplicate webhooks, and a customer who closes the tab mid-payment.
• Decide your refund process before your first refund request.

For gateways, cards and the legal side, see payment integration for Thai websites.

Get a free quote. We reply within 24 hours.