PayNow Decoder

A TypeScript library for decoding PayNow QR codes and extracting payment information.

Installation

npm install paynow-decoder

Usage

import { PayNowDecoder } from 'paynow-decoder';

const payload = '...'; // Your PayNow QR code payload
const decodedData = PayNowDecoder.decode(payload);
console.log(decodedData);
/* Output:
{
  payloadFormat: "01",
  pointOfInitiation: "12",
  merchantAccountInfo: {
    identifier: "SG.PAYNOW",
    proxyType: "mobile", // or "uen"
    proxyValue: "+6512345678",
    amountEditable: true,
    expiryDate: "20241130230000"
  },
  merchantCategoryCode: "0000",
  currencyCode: "702",
  transactionAmount: 99.99,
  countryCode: "SG",
  merchantName: "TEST COMPANY",
  merchantCity: "Singapore",
  additionalData: {
    referenceNumber: "TESTQRCODE"
  },
  crc: "2A56"
}
*/

Features

• Decodes PayNow QR codes for both UEN and mobile number recipients
• Extracts complete payment information including:
  • Proxy type (UEN/mobile)
  • Proxy value
  • Transaction amount
  • Reference number
  • Merchant details
  • Expiry date
  • Amount editability

Technical Details

QR Code Structure

Each PayNow QR code consists of data objects with three components:

1. ID (00-99)
2. Length of value (01-99)
3. Value

For example, in "000201", "00" is the ID, "02" is the length, and "01" is the value.

Key Fields

• Payload Format (ID 00): Always "01" for current version
• Point of Initiation (ID 01):
  • "11" for static QR (reusable)
  • "12" for dynamic QR (one-time use)
• Merchant Account Info (ID 26):
  • Contains nested PayNow-specific data:
    • Identifier: Fixed as "SG.PAYNOW"
    • Proxy Type: "0" for mobile, "2" for UEN
    • Proxy Value: Mobile (+65XXXXXXXX) or UEN number
    • Amount Editable: "0" for fixed, "1" for editable
• Currency Code (ID 53): "702" for SGD
• Country Code (ID 58): "SG" for Singapore
• CRC (ID 63): Checksum calculated using CRC-16-CCITT

License

MIT

References

• Python PayNow QR Code Generator - A helpful reference implementation for PayNow QR code structure