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, type-safe Bakong API client
• ✅ QR Generation: Generate static and dynamic KHQR codes
• 🖼️ SVG Rendering: Render KHQR payloads as portable payment banners
• 🔍 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',
  authToken: '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',
  expirationTimestamp: Date.now() + 3600000, // 1 hour from now
})

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)
}

SVG Rendering

Render a validated KHQR payload as a self-contained SVG payment banner. The standalone subpath is browser-safe, DOM-independent, and can also be used during server-side rendering.

import {
  generateKHQRSVG,
  svgToDataURI,
} from '@manethpak/khqr-sdk/svg'

if (dynamicQR.result) {
  const rendered = generateKHQRSVG(dynamicQR.result.qr)

  if (rendered.result) {
    const imageSource = svgToDataURI(rendered.result)
    console.log(imageSource) // Use as an <img src> value
  }
}

The renderer reads the merchant name, amount, and currency from the KHQR payload. Static payloads are supported and omit the amount line.

It is also available on an initialized SDK instance:

const rendered = khqr.svg.generateKHQRSVG(qrString)

Bakong API Integration

// Check Bakong account. The method name matches the current public API.
const account = await khqr.api.check_backong_account('user@bank')

if (account.responseCode === 0) {
  console.log('Account exists')
}

if (staticQR.result) {
  // Check transaction by MD5
  const transaction = await khqr.api.check_transaction_by_md5(
    staticQR.result.md5
  )

  // Generate deeplink for mobile apps
  const deeplink = await khqr.api.generate_deeplink({
    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
  expirationTimestamp: Date.now() + 3600000,
}

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
• Required 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'

// SVG renderer
import { generateKHQRSVG, svgToDataURI } from '@manethpak/khqr-sdk/svg'

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

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

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

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

ERROR_CODES.INVALID_QR
ERROR_CODES.INVALID_AMOUNT
ERROR_CODES.INVALID_ACCOUNT
ERROR_CODES.REQUIRED_FIELD
ERROR_CODES.INVALID_FORMAT
ERROR_CODES.CRC_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,
} from '@manethpak/khqr-sdk/types'
import type { Result } from '@manethpak/khqr-sdk/helper'

// Strongly typed API responses
const response = await khqr.api.check_backong_account('user@bank')
// response is typed as CheckBakongAccountResponse

Examples

Check out the /example directory for a complete Astro 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:

• renew_token(email) - Refresh authentication token
• generate_deeplink(input) - Generate mobile app deeplinks
• check_transaction_by_md5(md5) - Check transaction by MD5 hash
• check_transaction_by_hash(hash) - Check transaction by hash
• check_transaction_by_short_hash(input) - Check transaction by short hash
• check_transaction_by_instruction_ref(instructionRef) - Check by instruction reference
• check_transaction_by_external_ref(externalRef) - Check by external reference
• check_transaction_by_md5_list(md5List) - Check multiple MD5 hashes
• check_transaction_by_hash_list(hashList) - Check multiple hashes
• check_backong_account(accountId) - Verify Bakong account existence

These methods are available on khqr.api.

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.

Make a donation

Support me with a small donation, your support is appreciated!

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Made with ❤️ for the Cambodian fintech community