Kreiseck — Software Solutions

Kasseneck Flutter API

The Austrian RKSV-compliant cash register, right inside your Flutter app.
Issue signed receipts, take card payments and print — in a few lines of Dart.

platform RKSV compliant

kasseneck_api is the official Flutter client for Kasseneck — a fully RKSV-compliant (Austrian Registrierkassensicherheitsverordnung) point-of-sale backend by Kreiseck Software Solutions. It takes care of the signed Datenerfassungsprotokoll, card-payment terminals, receipt printing and PDF reports, so you can focus on your app.

🔑 You need an API key & a cashregister token to operate a register. Request yours at office@kreiseck.com · kreiseck.com

✨ Features

🧾 RKSV receipts — standard, cancellation, zero & training; signed JWS chain + QR code
💶 All Austrian VAT rates — incl. the new 4.9 % Grundnahrungsmittel rate (from 1 Jul 2026)
💳 Card payments out of the box — Hobex (Cloud & on-terminal HPS), myPOS, GP Tom, SumUp — and any other method via CreditCardProvider.custom
🎟️ Vouchers — value & promo, sell & redeem, with proportional VAT split
🖨️ Printing — Bluetooth & Wi-Fi (ESC/POS) plus the myPOS built-in printer
📱 Drop-in receipt widget for on-screen display
📊 Reports & invoices — daily / monthly PDF
🔗 Stripe payment links for remote & online payments

🧩 Requirements

Flutter · Dart >= 3.6
A Kasseneck API key + cashregister token (→ Kreiseck)
An Android device/terminal for card payments & Bluetooth printing

📦 Installation

dependencies:
  kasseneck_api: ^2.1.0

flutter pub get

🚀 Quick start

import 'package:kasseneck_api/kasseneck_api.dart';
import 'package:kasseneck_api/models/kasseneck_item.dart';
import 'package:kasseneck_api/enums/vat_rate.dart';
import 'package:kasseneck_api/enums/keck_payment_method.dart';

final kasseneck = KasseneckApi(
  apiKey: 'YOUR_API_KEY',
  cashregisterToken: 'YOUR_CASHREGISTER_TOKEN',
);

// A cash sale with two items
final receipt = await kasseneck.sellReceipt(
  paymentMethod: KeckPaymentMethod.cash,
  customerDetails: ['Max Mustermann'],
  items: [
    KasseneckItem(name: 'Coffee', quantity: 2, vat: VatRate.vat20,      singlePrice: 3.20),
    KasseneckItem(name: 'Bread',  quantity: 1, vat: VatRate.vat4komma9, singlePrice: 2.40),
  ],
);

print('Receipt ${receipt?.receiptId} — signed: ${receipt?.signatureSuccess}');

💡 Models & enums live in their own files — import the ones you use (models/…, enums/…). Payment, refund, cancellation, zero & training receipts all run through the same KasseneckApi instance.

💳 Card payments

Card payments work out of the box with several terminals — and you're never locked in:

Method	How
Hobex Cloud	`kasseneck.hobexPay(...)` / `hobexRefund(...)`
Hobex HPS (local terminal)	`import 'package:kasseneck_api/hobex_hps.dart';` → `HpsClient`
myPOS · GP Tom · SumUp	supported & rendered on the receipt
Any other terminal/method	`CreditCardProvider.custom` — just pass your own card data

Whatever terminal you use, hand the result to sellReceipt(...) as cardPaymentData and it is stored and printed on the receipt.

Example — local Hobex terminal (HPS) → signed receipt

import 'package:kasseneck_api/hobex_hps.dart'; // HpsClient, TransactionResponse, HobexReceipt

final hps = HpsClient(tid: '3600335'); // TID without leading zero

// 1) Charge the card on the terminal
final res = await hps.payment(amount: 12.50);
if (!res.isApproved) return; // declined -> res.responseCode / res.responseText

// 2) Adapt the terminal result, 3) create the signed receipt
final card = HobexReceipt.fromHps(res);
await kasseneck.sellReceipt(
  paymentMethod: KeckPaymentMethod.creditCard,
  creditCardProvider: card.creditCardProvider, // hobexHps
  cardPaymentId: card.transactionId,
  cardPaymentData: card.toCardPaymentData(),
  items: [KasseneckItem(name: 'Lunch', quantity: 1, vat: VatRate.vat10, singlePrice: 12.50)],
);

Also available: hps.refund(...), hps.cancel(...), hps.transactionStatus(...), hps.diagnosis(). A declined payment is not an exception — it's res.isApproved == false.

🖨️ Printing

// Bluetooth (ESC/POS)
await kasseneck.initBluetoothPrinter(printerAddress: 'AA:BB:CC:DD:EE:FF');
await receipt!.printReceiptBluetooth();

// Wi-Fi
await kasseneck.initWifiPrinter('192.168.0.50', KeckPaperSize.mm80);
await receipt.printReceiptWifi();

// Open the cash drawer
await KasseneckApi.openCashDrawer();

📱 On-screen receipt

A ready-made widget renders the full receipt (logo, items, VAT table, QR, card details):

KeckReceiptWidget(receipt: receipt);

📊 Reports & invoices

final monthly = await kasseneck.downloadMonthlyReport(ReportMonth.now()); // Uint8List (PDF)
final daily   = await kasseneck.downloadDailyReport(DateTime.now());
final history = await kasseneck.getReceipts(start, end);

🇦🇹 RKSV compliance

Every receipt is chained and signed (ES256 / JWS) and exposed as the machine-readable QR payload, exactly as required by the Austrian RKSV. Signature-device outages are detected (receipt.signatureSuccess / receipt.isSigFailed) and printed on the receipt.

🗂️ Versioning

This package follows semantic versioning — see the CHANGELOG. Latest: 2.1.0 — Hobex HPS integration, 4.9 % Grundnahrungsmittel rate, robustness hardening.

💬 Support

Kreiseck Software Solutions — office@kreiseck.com · kreiseck.com

📄 License

See LICENSE.