How PromptPay Works – Complete Guide

What is PromptPay?

How PromptPay Works – Step by Step

1. 1

   Recipient shares PromptPay QR or key

   The payee provides a phone number, National ID or a PromptPay QR code. Static QR codes work for any amount; dynamic QR codes include a pre-set amount for invoices and e-commerce.

2. 2

   Payer opens any Thai banking app

   All 30+ participating banks are fully interoperable. A payment from KBank arrives instantly in an SCB account — there is no lock-in to any specific institution.

3. 3

   Payer scans QR or enters phone/ID

   The app activates the camera for QR scanning, or the payer types the PromptPay key manually. The recipient's name is shown for confirmation.

4. 4

   Payment details confirmed on screen

   The recipient's name (as registered with ITMX) is displayed. If a dynamic QR is used, the amount is pre-filled. Static QR requires the payer to enter the amount.

5. 5

   Payer authenticates (biometric or PIN)

   Authentication happens entirely within the banking app. The PromptPay QR contains no passwords, PINs or sensitive banking credentials.

6. 6

   Transfer completes instantly

   The ITMX infrastructure routes the payment through the PromptPay network. Funds settle in real time between the two bank accounts — typically within 5 seconds.

7. 7

   Both parties receive app notification

   Sender and recipient both get instant push notifications. The payer's app shows a receipt with a transaction reference number for records.

PromptPay Keys – Phone vs National ID

The PromptPay QR Payload – EMV Format

000201                              ← Tag 00: Payload Format Indicator
010211                              ← Tag 01: Static QR (11)
2937                                ← Tag 29: Merchant Account (length 37)
  0016A000000677010111                ← Sub-tag 00: PromptPay AID
  01130066812345678                   ← Sub-tag 01: Normalized phone key
52040000                            ← Tag 52: Merchant Category Code
5303764                             ← Tag 53: Currency (THB = 764)
5406100.00                          ← Tag 54: Amount
5802TH                              ← Tag 58: Country Code
5903N/A                             ← Tag 59: Merchant Name
6007Bangkok                         ← Tag 60: Merchant City
62070503***                         ← Tag 62: Additional Data
6304ABCD                            ← Tag 63: CRC16 Checksum

Phone Number Normalization

• 1️⃣Start with a local Thai number: 0812345678
• 2️⃣Remove the leading 0: 812345678
• 3️⃣Prepend the country code prefix 0066: 0066812345678
• 🔁If the input starts with +66 (international format), replace the + with 00: +66812345678 → 0066812345678

function normalizePromptPayKey(key: string): string {
  const digits = key.replace(/\D/g, '');

  // National ID or Tax ID (13 digits) — use as-is
  if (digits.length === 13) return digits;

  // Phone number normalization
  if (digits.startsWith('0') && digits.length === 10) {
    return '0066' + digits.slice(1);   // 0812345678 → 0066812345678
  }
  if (digits.startsWith('66') && digits.length === 11) {
    return '00' + digits;              // 66812345678 → 0066812345678
  }
  return digits;
}

PromptPay's ASEAN Cross-Border Network

Supported Banks

PromptPay's Impact on Thailand

• 💸Interbank fees eliminated: The Bank of Thailand mandated free PromptPay transfers for amounts up to ฿5,000 in 2018, then extended this to all amounts in 2019 — effectively ending domestic transfer fees across all Thai banks.
• 📈Digital payment acceleration: Thailand jumped from primarily cash-based to one of the most digitally-transacting populations in Southeast Asia in just a few years, driven almost entirely by PromptPay adoption.
• 🏛️Government stimulus via PromptPay: During the COVID-19 pandemic, the Thai government distributed welfare and relief payments to millions of citizens directly via their National ID-linked PromptPay accounts — faster and cheaper than any alternative.
• 🛒Commerce transformation: From street food vendors and market stalls to major e-commerce platforms like Lazada and Shopee Thailand, PromptPay QR became the default checkout option — eliminating the need for card readers.
• 🌏Regional leadership: Thailand's PromptPay is cited by the Bank for International Settlements as one of the model systems for ASEAN payment interoperability, and has directly inspired similar linkages across the region.