Crypto

One catalog method — usdc — lets customers pay from any crypto wallet in USDC, the dollar-pegged stablecoin, on their choice of supported network. You price in your normal currency, and by default you settle in fiat: the stablecoin leg lives entirely inside the flow.

USDC in the catalog

Why one method and one asset: USDC is dollar-pegged (no price risk inside a checkout window), natively issued on multiple networks (cheap, fast transfers), and redeemable 1:1 — which is what makes clean fiat settlement possible. You pass "payment_method": "usdc"; everything network-specific happens on the hosted page.

The customer picks the network there — supported networks include Ethereum, Solana, Polygon, and Base — and pays from whatever wallet they hold: self-custodied or an exchange account. You never see addresses, networks, or gas; the Payment object stays the same shape as an iDEAL payment.

The payment flow

Step by step:

1. Quote & address

   The hosted page locks the USDC amount for your amount/currency and shows a one-time deposit address (with QR) on the customer's chosen network. One address per payment — that's what ties an incoming transfer to pay_8Q2mX4nT1cVb with no reference field to typo.

2. Transfer

   The customer sends the exact USDC amount from their wallet. The page watches the network and flips to "detected" when the transfer appears.

3. Finality

   When the transfer is final on-chain, the payment moves to succeeded and payment.succeeded fires. Fulfill on the webhook, as always — not on "detected".

Creating a USDC payment

Nothing crypto-specific in the request — price it like any payment:

curl https://api.finscale.dev/v1/payments \
  -H "Authorization: Bearer sk_test_51FinscaleDemo…" \
  -H "Idempotency-Key: idem_ord_9f21_0716" \
  -H "Content-Type: application/json" \
  -d '{
    "amount": 4900,
    "currency": "EUR",
    "payment_method": "usdc",
    "reference": "ord_9f21_0716",
    "customer": { "email": "anna@example.com" },
    "return_url": "https://shop.example.com/checkout/return"
  }'

{
  "id": "pay_8Q2mX4nT1cVb",
  "object": "payment",
  "amount": 4900,
  "currency": "EUR",
  "status": "requires_action",
  "payment_method": "usdc",
  "reference": "ord_9f21_0716",
  "next_action": {
    "type": "redirect",
    "url": "https://pay.finscale.dev/r/8Q2mX4nT"
  },
  "created_at": "2026-07-16T09:24:31Z",
  "livemode": false
}

Networks & finality

• Finality is network-dependent — seconds on fast chains, minutes on others. Finscale marks the payment succeeded only at finality; a transfer that appears and is then reorganized away never succeeds.
• The address is single-use and network-bound. Funds sent to it on the wrong network, or a different token sent to it, are not credited to the payment — recovery is handled case by case from the dashboard.
• Exact-amount matching. The quote pins the USDC amount. Underpayments don't complete the payment: the page prompts for the remainder until the quote window lapses, after which the partial transfer is returned to the sending address.

Settlement: fiat or USDC

Two account-level options, set per merchant:

• Fiat settlement (default). At finality, the USDC converts to your settlement currency and the funds join your unified payout on the standard T+2 schedule — one settlement line, payment id attached, exactly like card volume. Conversion works as described in Multicurrency.
• USDC settlement. Accounts configured for stablecoin payouts keep the USDC leg: funds accumulate as USDC and pay out on-chain instead of by bank transfer. Reports and reconciliation are unchanged.

Refunds — no chargebacks

POST /v1/refunds works as everywhere: full or partial, by payment id. The refund is pushed as a USDC transfer back to the on-chain sending address, and stays pending until that transfer reaches finality — subscribe to refund.succeeded.

Error scenarios

Related

• Payment methods overview — families, payload shapes, full catalog
• Multicurrency — presentment vs settlement currency
• Settlement & payouts — where converted funds land
• Reconciliation — id chains across rails, on-chain included
• Method catalog on finscale.dev — regions and currencies