@thai-qr-payment/payload

Zero-dependency EMVCo Merchant-Presented-Mode QR payload builder + parser for Thai QR Payment (PromptPay, BillPayment, KShop). Works in browsers, Node, Bun, Deno, and edge runtimes.

pnpm add @thai-qr-payment/payload

Quickstart

import { ThaiQrPaymentBuilder, parsePayload, payloadFor } from '@thai-qr-payment/payload';

// One-shot
const wire = payloadFor({ recipient: '0812345678', amount: 50 });

// Builder for full control
const advanced = new ThaiQrPaymentBuilder()
  .promptpay('0812345678')
  .amount(120.5)
  .merchant({ name: 'Acme Coffee', city: 'BANGKOK', categoryCode: '5814' })
  .additionalData({ billNumber: 'INV-2026-001' })
  .tipPolicy({ mode: 'prompt' })
  .build();

// Parser
const parsed = parsePayload(wire);

API

| Export | What it does | | ----------------------------------------------- | ----------------------------------------------------------------------------- | | ThaiQrPaymentBuilder | Chainable builder. Terminal: .build(), .buildWithChecksum(), .toBytes() | | parsePayload(wire) | Decode + validate CRC. Throws on tamper. | | payloadFor(input) | One-shot helper for PromptPay | | normaliseRecipient(input, type?) | Stand-alone recipient → wire format | | formatAmount(value, opts?) | Amount → 2-decimal string | | checksum(text) | CRC-16/CCITT-FALSE | | encodeField / parseFields / iterateFields | Low-level TLV | | Tags.* | Tag constants |

Recipient types

| Input length (digits) | Default type | Wire sub-tag | | --------------------- | ------------ | ------------ | | 9-10 | mobile | 01 | | 13 | nationalId | 02 | | 15 | eWallet | 03 |

Override with the explicit type arg.

Tip policy

.tipPolicy({ mode: 'prompt' })             // app asks the payer
.tipPolicy({ mode: 'fixed', value: 10 })   // fixed THB amount
.tipPolicy({ mode: 'percentage', value: 5 }) // 5%

Browser

@thai-qr-payment/payload is pure TS — no Node built-ins. Drop into Vite, Webpack, Rspack, Bun bundle. Tree-shakable.

License

MIT