What your customer sees

Once the frame opens, the flow is ours. It is worth knowing its shape.

• An amount, and an asset. They type a figure in euros and pick which crypto to buy. Which cryptos are on offer is part of our merchant configuration; if yours is set up with a single asset, there is no picker — the customer just sees what they are buying. A live quote sits under the amount: what it will buy at the current price, and the fees — our row, and a second row with your own fee when you charge one. Fees are always on screen, never behind a disclosure. A consent line naming the amount and your business gates the Pay button.
• An identity check, once. On a customer's first payment they are taken through KYC inside the frame. It is a one-time step: a returning customer who has been approved goes straight from the amount to the card.
• A card payment on a hosted payment page — a form served from our payment provider's own domain, loaded inside the widget. Card details never touch your code, and never touch ours either. 3-D Secure runs there when the card requires it.
• A receipt. When the crypto has been bought and credited, the widget shows what actually happened: the crypto bought, the money paid, the same fee rows as the quote, the price and a reference the customer can quote to support.

The price on the receipt is the price the crypto was really bought at, at the moment the payment was captured. The quote shown while the customer types is indicative and moves with the market, so the two figures are close but need not be identical.

Fees

When Kvarn has enabled it for your account, you may charge your own fee per payment, on top of ours, by signing merchantFeeBps into the token (basis points, 0–2000; omit it to charge none). The customer sees both fees as separate rows, with their percentages, on the quote and on the receipt. Both are deducted from the amount the customer typed, not added on top of it: the fees are taken first and the crypto is bought with the remainder. Your fee is fiat owed to you; the final figures are on the payment.credited event.

What it means for you

The crypto is credited to your account in Kvarn's ledger, attributed to the customer reference you asserted in sub. That attribution is why sub has to be stable: it is how a balance is traced back to the person who brought it in. Nothing moves on-chain per payment; accumulated balances are transferred out to you separately.

Which assets your customers can buy is configured per merchant when your account is set up — the widget offers exactly the assets enabled for you, and nothing else. Talk to Kvarn to change the list.

What the widget cannot tell you is what your own systems should do next. That is what payment events are for.