Conversion

Conversion is part of a Payment or an inbound transfer into a reusable bank funding account. There is no Conversion resource and no convert endpoint.

Conversion applies in three cases

Situation	What converts
The payer holds a different chain or asset than the recipient wants	Crypto to crypto, across chains if needed
An off-ramp pays out local currency	Stablecoin to fiat
An on-ramp collects local currency	Fiat to stablecoin

If payer and recipient are already on the same chain and asset, nothing converts and no quote is involved. Crypto-to-crypto routing runs on the supported chains; fiat conversion is limited to the corridors where collection or payout is enabled. View supported regions and currencies → On a receive payment, the conversion is chosen when the payer selects an option. Selecting it fixes the chain, the asset and the amount the payer owes, and the recipient’s amount does not change with how the payer funds it.

Read the quote where it appears

There is no quote resource. A quote is a frozen rate with a deadline, and it appears in two places.

Where	Fields	Expiry
On a payment option	`sourceAmount`, `payerAmount`, `recipientAmount`, `providerFee`	`expiresAt`, the effective payer deadline
On an external fiat send	`funding.exchangeRate`, with `rate`, `baseAssetCode`, `quoteAssetCode`	`funding.quoteExpiresAt`

Where a quote has a deadline, the funding window ends at the earlier of the Payment’s expiresAt and the quote’s expiry. Show the returned figures. Refresh a checkout option only when eligible and no payment evidence has been observed. The US linked-bank route fixes the crypto input without locking a USD rate. Its final USD delivery and conversion costs are known only at settlement; do not display a guaranteed dollar amount.

Handle an expired quote by where it lived

Both cases return payment_quote_expired. What you do next differs.

Expired quote	Do this
A payment option at checkout	When `refreshable` is true and no payment evidence has been observed, refresh the option on the existing payment with `POST /v2/public/payments/{paymentId}/options/{optionId}/refresh`. Do not create a new payment
`funding` on a fiat send	The quote cannot be refreshed. Read the original Payment and reconcile any funds sent. A new attempt requires a terminal original Payment and a new idempotency key. See Sending payments

Preview a send before anything exists

POST /v2/payments/preview resolves the destination, the fee and the funding options with no financial side effect. It covers only upa, payment_handle and crypto_wallet send destinations. External fiat sends resolve funding terms at creation; receive Payments expose payer options after creation.

curl -X POST https://staging-api-v2.stableyard.fi/v2/payments/preview \
  -u "$APP_ID:$APP_SECRET" \
  -H "Content-Type: application/json" \
  -d '{
    "intent": "send",
    "sender": { "accountId": "acct_123" },
    "destination": { "type": "payment_handle", "paymentHandle": "alice@partner" },
    "paymentAmount": { "amount": "100.00", "assetCode": "USDC" }
  }'

Next: Fees

How each fee is set, frozen onto a payment and deducted once.

Concepts

Onboarding

Money movement

Automation

Webhooks

Reference data

Conversion applies in three cases

Read the quote where it appears

Handle an expired quote by where it lived

Preview a send before anything exists

Next: Fees

​Conversion applies in three cases

​Read the quote where it appears

​Handle an expired quote by where it lived

​Preview a send before anything exists

Next: Fees

Conversion applies in three cases

Read the quote where it appears

Handle an expired quote by where it lived

Preview a send before anything exists