Money and currencies

Minor units#

An amount is an integer in the smallest unit of the currency. For the euro, the minor unit is the cent.

Currency codes#

A currency is an ISO 4217 alphabetic code in upper case, for example EUR. The pattern is ^[A-Z]{3}$.

Two shapes of amount#

The API uses two shapes, depending on the resource.

On transactions, an amount is a plain integer. The currency is the currency field of the transaction:

{
  "currency": "EUR",
  "amounts": { "subtotal": 12000, "discount": 0, "net": 12000, "tax": 2280, "total": 14280 },
  "remainingCollectibleAmount": 14280
}

On payments, refunds, and checkout sessions, an amount is a Money object with its own currency:

{ "amountMinor": 14280, "currency": "EUR" }

Payment links use plain integers with a Minor suffix, such as amountMinor and minimumAmountMinor, next to a currency field.

Webhook payloads use plain integers, with a currency field on the object.

Rules#

• A transaction has one currency. Every line must use a price in that currency. Otherwise the request returns 422 with currency_mismatch.
• A transaction amount can be 0. A payment amount must be greater than 0.
• A refund must use the currency of the payment, and cannot be more than the amount that is not yet refunded.
• Merxian calculates the tax and the total of a transaction from catalog prices. Read the amounts from the response. Do not calculate the total yourself. See Transactions.