KHQR SDK

TypeScript SDK for generating, decoding, and validating KHQR (Cambodia's Bakong QR payment codes) following the EMV QR Code specification.

Live demo

⚠️ Note: This is a community-maintained SDK and is not officially endorsed or supported by Bakong or the National Bank of Cambodia. Use at your own discretion.

Features

• 🎯 Type-Safe: Full TypeScript support with comprehensive type definitions
• 🔒 EMV Compliant: Follows EMV QR Code specification standards
• 🏦 Bakong API Integration: Ready-to-use Bakong API client with Zod validation
• ✅ QR Generation: Generate static and dynamic KHQR codes
• 🔍 QR Validation: Decode and verify KHQR strings with CRC integrity checks
• 📦 Support: ESM and CommonJS exports

Installation

npm install @manethpak/khqr-sdk

yarn add @manethpak/khqr-sdk

pnpm add @manethpak/khqr-sdk

Quick Start

QR Code Generation

import { createKHQR } from '@manethpak/khqr-sdk'

// Initialize the SDK
const khqr = createKHQR({
  baseURL: 'https://api-bakong.nbc.gov.kh',
  auth: {
    type: 'Bearer',
    token: 'your_bakong_api_token',
  },
})

// Generate a static QR code (no amount)
const staticQR = khqr.qr.generateKHQR({
  bakongAccountID: 'user@bank',
  merchantName: 'Coffee Shop',
  merchantCity: 'Phnom Penh',
  currency: 'KHR',
})

if (!staticQR.error) {
  console.log('QR Code:', staticQR.result?.qr)
  console.log('MD5 Hash:', staticQR.result?.md5)
}

// Generate a dynamic QR code (with amount)
const dynamicQR = khqr.qr.generateKHQR({
  bakongAccountID: 'merchant@aclb',
  merchantName: 'Coffee Shop',
  merchantCity: 'Phnom Penh',
  amount: 10000,
  currency: 'KHR',
})

if (!dynamicQR.error) {
  console.log('QR Code:', dynamicQR.result?.qr)
  console.log('MD5 Hash:', dynamicQR.result?.md5)
}

QR Code Decoding

const qrString = '00020101021229180...' // Your KHQR string

const decoded = khqr.qr.decodeKHQR(qrString)

if (!decoded.error) {
  console.log('Decoded Data:', decoded.result)
}

QR Code Verification

const verification = khqr.qr.verifyKHQRString(qrString)

if (!verification.error && verification.result?.isValid) {
  console.log('QR code is valid!')
  console.log('Expected CRC:', verification.result.expectedCRC)
  console.log('Actual CRC:', verification.result.actualCRC)
} else {
  console.error('Validation errors:', verification.result?.errors)
}

Bakong API Integration

// Check Bakong account
const { data, error } = await khqr.$fetch('/v1/check_bakong_account', {
  body: {
    accountId: 'user@bank',
  },
})

if (!error) {
  console.log('Account Info:', data)
}

// Check transaction by MD5
const transaction = await khqr.$fetch('/v1/check_transaction_by_md5', {
  body: {
    md5: staticQR.result?.md5,
  },
})

// Generate deeplink for mobile apps
const deeplink = await khqr.$fetch('/v1/generate_deeplink_by_qr', {
  body: {
    qr: staticQR.result?.qr,
    sourceInfo: {
      appIconUrl: 'https://example.com/icon.png',
      appName: 'My Payment App',
      appDeepLinkCallback: 'myapp://payment/callback',
    },
  },
})

API Reference

QR Generation

generateKHQR(info: IndividualInfo | MerchantInfo): Result<QRResult>

Generates a KHQR code with automatic type detection.

Individual Account Example:

const info: IndividualInfo = {
  bakongAccountID: 'user@bank',
  merchantName: 'John Doe',
  merchantCity: 'Phnom Penh',
  currency: 'KHR',
  amount: 50000,
  billNumber?: 'INV-001',
  mobileNumber?: '+85512345678',
  storeLabel?: 'Main Store',
  terminalLabel?: 'POS-01',
  purposeOfTransaction?: 'Payment for goods',
  expirationTimestamp?: Date.now() + 3600000 // 1 hour from now
}

Merchant Account Example:

const info: MerchantInfo = {
  bakongAccountID: 'merchant@bank',
  merchantID: 'MERCHANT123',
  merchantName: 'Big Store',
  merchantCity: 'Phnom Penh',
  acquiringBank: 'ACLB',
  currency: 'USD',
  amount: 25.99,
  merchantCategoryCode: '5411', // Grocery stores
}

Return Type:

interface QRResult {
  qr: string // EMV-compliant QR string
  md5: string // MD5 hash for transaction tracking
}

decodeKHQR(qrString: string): Result<DecodedKHQRData>

Decodes a KHQR string into its constituent parts.

verifyKHQRString(qrString: string): Result<VerifyStringResult>

Verifies the structural validity and CRC integrity of a KHQR string.

Currency Support

• KHR (Khmer Riel): Must be whole numbers only
• USD (US Dollar): Supports up to 2 decimal places

// Valid KHR amounts
amount: 10000 // ✅
amount: 50000 // ✅

// Invalid KHR amounts
amount: 10000.5 // ❌ No decimals allowed

// Valid USD amounts
amount: 25.99 // ✅
amount: 100 // ✅

// Invalid USD amounts
amount: 25.999 // ❌ Max 2 decimals

QR Code Types

The SDK automatically detects QR code types based on input:

Static QR (amount is 0 or undefined):

• Point of Initiation Method = "11"
• No amount field in QR code
• User scans and enters amount manually

Dynamic QR (amount > 0):

• Point of Initiation Method = "12"
• Fixed amount in QR code
• Optional expiration timestamp

Individual vs Merchant:

• Individual: Has bakongAccountID but no merchantID
• Merchant: Has both bakongAccountID and merchantID

Subpath Exports

Import only what you need to reduce bundle size:

// Main SDK
import { createKHQR } from '@manethpak/khqr-sdk'

// Constants only
import { EMV_TAGS, CURRENCY_CODES } from '@manethpak/khqr-sdk/constants'

// Helper utilities
import { validators, calculateCRC16 } from '@manethpak/khqr-sdk/helper'

// Type definitions
import type {
  IndividualInfo,
  MerchantInfo,
  QRResult,
} from '@manethpak/khqr-sdk/types'

Error Handling

The SDK uses a Result<T> pattern instead of throwing exceptions:

const result = khqr.qr.generateKHQR(info)

if (result.error) {
  // Handle KHQRError
  console.error('Error code:', result.error.code)
  console.error('Message:', result.error.message)
  console.error('Details:', result.error.details)
} else {
  // Use result.result
  const { qr, md5 } = result.result
}

Error Codes

{
  INVALID_QR: 'Invalid QR code format',
  INVALID_AMOUNT: 'Invalid amount for currency',
  INVALID_ACCOUNT: 'Invalid account information',
  REQUIRED_FIELD: 'Required field missing',
  INVALID_FORMAT: 'Invalid format',
  CRC_INVALID: 'CRC checksum is invalid'
}

Advanced Usage

Custom Validation

import { validators } from '@manethpak/khqr-sdk/helper'

const validation = validators.validateIndividualInfo({
  bakongAccountID: 'user@bank',
  merchantName: 'Test',
  merchantCity: 'PP',
})

if (!validation.isValid) {
  console.error('Validation errors:', validation.errors)
}

CRC Calculation

import { calculateCRC16 } from '@manethpak/khqr-sdk/helper'

const payload = '00020101021229180...'
const crc = calculateCRC16(payload + '6304')
console.log('CRC16:', crc) // e.g., "A1B2"

Language Support

Add alternate language fields for bilingual QR codes:

const qr = khqr.qr.generateKHQR({
  bakongAccountID: 'user@bank',
  merchantName: 'Coffee Shop',
  merchantCity: 'Phnom Penh',
  languagePreference: 'km',
  merchantNameAlternateLanguage: 'ហាងកាហ្វេ',
  merchantCityAlternateLanguage: 'ភ្នំពេញ',
})

TypeScript Support

Full TypeScript support with comprehensive type definitions:

import type {
  IndividualInfo,
  MerchantInfo,
  QRResult,
  DecodedKHQRData,
  CurrencyType,
  Result,
} from '@manethpak/khqr-sdk/types'

// Strongly typed API responses
const response = await khqr.$fetch('/v1/check_bakong_account', {
  body: { accountId: 'user@bank' },
})
// response.data is fully typed based on the endpoint

Examples

Check out the /example directory for a complete Hono.js server integration:

cd example
pnpm install
pnpm dev

Development

# Install dependencies
pnpm install

# Build the package
pnpm build

# Run tests
pnpm test

# Run tests with coverage
pnpm coverage

# Lint code
pnpm lint:fix

# Format code
pnpm format

Bakong API Endpoints

The SDK includes type-safe wrappers for all Bakong API endpoints:

• /v1/renew_token - Refresh authentication token
• /v1/generate_deeplink_by_qr - Generate mobile app deeplinks
• /v1/check_transaction_by_md5 - Check transaction by MD5 hash
• /v1/check_transaction_by_hash - Check transaction by hash
• /v1/check_transaction_by_short_hash - Check transaction by short hash
• /v1/check_bakong_account - Verify Bakong account existence

Requirements

• Node.js >= 20
• TypeScript >= 5.0 (for TypeScript users)

License

ISC © Manethpak

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

Related Links

• Bakong Official Documentation
• EMV QR Code Specification
• GitHub Repository

Support

If you encounter any issues or have questions, please open an issue on GitHub.

Made with ❤️ for the Cambodian fintech community