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A debit card connects to OMS in two directions. As a funding source, a card payment converts to USDC and tops up a customer’s wallet (an on-ramp). As a payout destination, OMS pushes a wallet balance out to a cardholder’s debit card (an off-ramp). Both run through the standard quote-and-transaction flow; only the asset, network, and destination reference change.
Debit card external accounts (pmCard_) and on-ramping via a debit card are part of early-access onboarding rather than through a public endpoint. To be notified when debit cards launch, please register your interest.

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Share your use case and we’ll reach out when debit card support is available.

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Two roles

RoleTransactionWhat happensReference
Funding sourcefiatToCryptoA card payment converts to USDC and credits a walletSource asset: usd, network: card
Payout destinationcryptoToFiatA wallet balance is pushed to the cardholder’s debit cardDestination externalAccount: pmCard_...

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Card as a funding source

A card-funded on-ramp uses the card rail on the transaction source. The customer pays with their debit card and OMS delivers USDC to the destination wallet. 
{
  "customerId": "cst_...",
  "source": {
    "asset": "usd",
    "network": "card",
    "amount": "100.00"
  },
  "destination": {
    "wallet": { "wallet": "wlt_..." },
    "asset": "usdc",
    "network": "polygon"
  }
}
The quote and transaction structure follows the standard fiat-to-crypto flow.

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Card as a payout destination

A debit card is registered as an external account with the pmCard_ prefix, then referenced by ID as the destination of a cryptoToFiat transaction. OMS pushes the payout to the card. As with all external accounts, the quote source is always an OMS wallet, so a card is used as a destination, never a source. 
{
  "customerId": "cst_...",
  "source": {
    "walletId": "wlt_...",
    "asset": "usdc",
    "network": "polygon",
    "amount": "100.00"
  },
  "destination": {
    "wallet": { "externalAccount": "pmCard_..." },
    "asset": "usd",
    "network": "card"
  }
}