VietnamQrPay

VietnamQrPay is a dependency-free Ruby implementation of Vietnamese payment QR standards.

It ports the core behavior of the original xuannghia/vietnam-qr-pay JavaScript library and provides a Ruby-idiomatic API for:

Encoding VietQR payloads
Encoding VNPayQR payloads
Decoding VietQR, VNPayQR, and related EMVCo-style QR payloads
Working with the upstream bank catalog and supported bank app metadata
Building MoMo and ZaloPay receive QR payloads that are represented as VietQR over BVBank accounts

Features

No runtime dependencies
Pure Ruby CRC16-CCITT implementation
Ruby-style module and method naming
Public bank constants ported from the JavaScript reference
Test coverage based on the upstream fixtures and expected payloads
Ready-to-publish gem metadata for RubyGems

Documentation

Installation

Install from RubyGems:

gem install vietnam_qr_pay

Or add it to your Gemfile:

gem "vietnam_qr_pay"

Then require it:

require "vietnam_qr_pay"

Quick Start

Build a static VietQR

require "vietnam_qr_pay"

qr = VietnamQrPay::QRPay.init_viet_qr(
  bank_bin: VietnamQrPay::BanksObject[:acb].bin,
  bank_number: "257678859"
)

qr.build
# => "00020101021138530010A0000007270123000697041601092576788590208QRIBFTTA53037045802VN6304AE9F"

Build a dynamic VietQR

require "vietnam_qr_pay"

qr = VietnamQrPay::QRPay.init_viet_qr(
  bank_bin: VietnamQrPay::BanksObject[:acb].bin,
  bank_number: "257678859",
  amount: "10000",
  purpose: "Chuyen tien"
)

qr.build
# => "00020101021238530010A0000007270123000697041601092576788590208QRIBFTTA53037045405100005802VN62150811Chuyen tien630453E6"

Build a VNPayQR payload

require "vietnam_qr_pay"

qr = VietnamQrPay::QRPay.init_vnpay_qr(
  merchant_id: "0102154778",
  merchant_name: "TUGIACOMPANY",
  store: "TU GIA COMPUTER",
  terminal: "TUGIACO1"
)

qr.build
# => "00020101021126280010A0000007750110010215477853037045802VN5912TUGIACOMPANY62310315TU GIA COMPUTER0708TUGIACO16304DF44"

Decode a QR payload

require "vietnam_qr_pay"

payload = "00020101021238530010A0000007270123000697041601092576788590208QRIBFTTA5303704540410005802VN62150811Chuyen tien6304BBB8"
qr = VietnamQrPay::QRPay.new(payload)

qr.valid?                       # => true
qr.provider.name               # => "VIETQR"
qr.consumer.bank_bin           # => "970416"
qr.consumer.bank_number        # => "257678859"
qr.amount                      # => "1000"
qr.additional_data.purpose     # => "Chuyen tien"

Supported Payment Flows

VietQR

Use VietnamQrPay::QRPay.init_viet_qr for bank-account or card-based VietQR payloads.

qr = VietnamQrPay::QRPay.init_viet_qr(
  bank_bin: VietnamQrPay::BanksObject[:acb].bin,
  bank_number: "257678859",
  service: VietnamQrPay::VietQRService::BY_ACCOUNT_NUMBER
)

MoMo and ZaloPay receive QR

The JavaScript reference treats these as VietQR payloads routed through BVBank. This gem keeps the same model.

MoMo example:

account_number = "99MM24011M34875080"

qr = VietnamQrPay::QRPay.init_viet_qr(
  bank_bin: VietnamQrPay::BanksObject[:banviet].bin,
  bank_number: account_number
)

qr.additional_data.reference = "MOMOW2W#{account_number[10..]}"
qr.set_unreserved_field("80", "046")

qr.build
# => "00020101021138620010A00000072701320006970454011899MM24011M348750800208QRIBFTTA53037045802VN62190515MOMOW2W3487508080030466304EBC8"

ZaloPay example:

qr = VietnamQrPay::QRPay.init_viet_qr(
  bank_bin: VietnamQrPay::BanksObject[:banviet].bin,
  bank_number: "99ZP24009M07248267"
)

qr.build
# => "00020101021138620010A00000072701320006970454011899ZP24009M072482670208QRIBFTTA53037045802VN6304073C"

Generic decode support

VietnamQrPay::QRPay.new(payload) will also decode provider variants such as AirPay and non-standard EMVCo-style payloads, as long as the CRC is valid. Unknown providers keep their raw provider GUID and provider data so the payload can still be inspected or rebuilt.

Public API

Main class

VietnamQrPay::QRPay

valid? / is_valid
build
parse
set_evmco_field
set_unreserved_field
.init_viet_qr
.init_vnpay_qr
.verify_crc
.gen_crc_code

Data objects

VietnamQrPay::Provider
VietnamQrPay::Merchant
VietnamQrPay::Consumer
VietnamQrPay::AdditionalData
VietnamQrPay::Bank
VietnamQrPay::BankApp

Catalog constants

VietnamQrPay::BankKey
VietnamQrPay::BankCode
VietnamQrPay::BanksObject
VietnamQrPay::Banks
VietnamQrPay::BankApps
VietnamQrPay.bank(:acb)
VietnamQrPay.bank_app(:acb)

Bank Lookup Helpers

The generated catalog is available both as constants and convenience helpers:

bank = VietnamQrPay.bank(:vietinbank)
bank.bin
# => "970415"

app = VietnamQrPay.bank_app(:vietinbank)
app&.package_id
# => "com.vnpay.vietinbank"

Module Naming and Folder Structure

The gem uses standard Ruby naming:

Top-level namespace: VietnamQrPay
Main QR class: VietnamQrPay::QRPay
Constant modules: VietnamQrPay::BankKey, VietnamQrPay::BankCode, VietnamQrPay::QRProvider
Mutable QR payload objects: Provider, Merchant, Consumer, AdditionalData

The project layout is split by responsibility:

lib/
  vietnam_qr_pay.rb
  vietnam_qr_pay/
    version.rb
    constants.rb
    crc16.rb
    qr_pay.rb
    catalog.rb
    catalog/
      bank_keys.rb
      bank_codes.rb
      banks.rb
      bank_apps.rb
    models/
      provider.rb
      merchant.rb
      consumer.rb
      additional_data.rb
      bank.rb
      bank_app.rb
script/
  generate_catalog.rb
test/
  *_test.rb

script/generate_catalog.rb is intentionally kept in the repository so you can re-sync the bank catalog from the upstream JavaScript reference later without hand-editing large constant files.

Development

Run the test suite:

bundle exec rake test

Build the gem:

bundle exec rake build

Refresh the bank catalog from the bundled JavaScript reference:

ruby script/generate_catalog.rb

The generator expects the upstream JavaScript source to be available at references/vietnam-qr-pay-javascript.

For deeper implementation notes and release workflow, see the files under docs/.

Compatibility Notes

This gem follows the bundled JavaScript reference for payload structure and expected examples.
The Ruby API is intentionally snake_case instead of camelCase.
Builder instances created with init_viet_qr and init_vnpay_qr start in a valid state, which is more natural for Ruby than marking empty objects invalid.
set_evmco_field writes to the EVMCo field set directly.

Credits

Original JavaScript library: xuannghia/vietnam-qr-pay
Ruby port and packaging: this repository

License

Released under the MIT License. See LICENSE.