Ask Seismic to provision a virtual bank account for the customer. Shape and rails are inferred from currency (USD → ACH + wire, EUR → SEPA + SWIFT, …). Pass liquidation to auto-convert incoming fiat to a crypto account.

An approved customer is not automatically cleared for every currency: virtual-account access is granted per currency, and GET /v0/customers/{id}/virtual-account-approvals reports where each one stands. Requesting a currency the customer is not cleared for returns 409 VirtualAccountNotApproved — retrying will not change the answer until that clearance is granted.

Pass bank to say where the account is held, using a value from GET /v0/customers/{id}/virtual-account-banks?currency={currency}. Omit it and a bank is chosen for you. A bank the customer cannot be issued an account at returns 409 VirtualAccountBankNotAvailable and creates nothing. Where the account has its own review, a bank that review has not cleared returns 409 VirtualAccountNotApproved with the review's status instead, unless the request restores an account the customer deleted at that bank.

A customer may hold one virtual bank account per bank in a currency, so a bank they hold no account at is not a duplicate of the account they already have. Omitting bank asks for an account in the currency rather than one at a particular bank, and is answered by whichever account they already hold.

{
  "bank": "PORTAGE_BANK"
}