Tills, shops and messaging, connected

A till identifies the buyer by phone, e-mail, card number or a code from the app, asks for a quote, and commits the receipt after payment. Each call is a POST with a JSON body and a bearer key issued in the back office; keys bind to a location or stay global.

The engine does the money work: first-match rules, split of the write-off across earned, gifted and promo balances, caps per item and per cart, promo codes, gift certificates, a reserve that holds points while the cashier finishes, confirmation codes for write-off, receipt texts, and idempotency by the external receipt id so a retried request never doubles a sale.

Amounts travel in the tenant's currency with its own number of decimals (euros with two, yen with none) and are stored in minor units. One point equals one unit of currency.

Group	Calls	Examples
Customer	14	buyer-register, buyer-info, buyer-edit, buyer-bonus, purchase-list, groups
Purchase	10	purchase-dry-run, purchase, purchase-info, edit, cancel, change status, purchase-request with a reserve, write-off-request
Confirmation codes	5	send and verify registration, write-off and custom codes
Gift certificates	4	issue, check, redeem, cancel
Mobile app, additional, service	8	app tokens, promo code check, health

All 41 calls of the till API

POST /v2/purchase
Authorization: Bearer <till key>

{
  "phone": "+4915112345678",
  "external_purchase_id": "receipt-2026-10-22-0417",
  "sale_point": "Berlin Mitte",
  "write_off_bonus": 10,
  "items": [
    { "name": "Espresso beans 1 kg", "amount": 100.50, "quantity": 1 },
    { "name": "Filter paper",        "amount": 20.00,  "quantity": 2 }
  ]
}

HTTP 200
{
  "success": true,
  "purchase_amount": 120.5,
  "payment_amount": 110.5,
  "total_write_off_bonus": 10,
  "total_write_on_bonus": 11,
  "balance": 51,
  "items": [
    { "amount": 100.5, "payment": 90.5, "write_on_bonus": 9, "write_off_available": 51 },
    { "amount": 20,    "payment": 20,   "write_on_bonus": 2, "write_off_available": 51 }
  ],
  "print_on_check": "You earned 11 points. Balance: 51."
}