Highnote Documentation
Modern payment infrastructure, built for developers.
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One key, one endpoint, and a test environment that behaves like production. Simulate authorizations, refunds, and statements before you talk to anyone.
mutation CreateUSBusinessAccountHolder { createUSBusinessAccountHolder(input: { businessProfile: { name: { legalBusinessName: "Acme Fleet Co." } } primaryAuthorizedPerson: { name: { givenName: "Jordan", familyName: "Lee" } email: "jordan@acmefleet.com" } }) { ... on USBusinessAccountHolder { id } } }mutation CreateAccountHolderCardProductApplication { createAccountHolderCardProductApplication(input: { cardProductId: "<CARD_PRODUCT_ID>" accountHolderId: "<ACCOUNT_HOLDER_ID>" cardHolderAgreementConsent: { primaryAuthorizedPersonId: "<PERSON_ID>" consentTimestamp: "2026-08-20T12:00:00Z" } }) { ... on AccountHolderCardProductApplication { id applicationState { status } } } }mutation IssuePaymentCardForApplication { issuePaymentCardForApplication(input: { applicationId: "<APPLICATION_ID>" options: { expirationDate: "2029-08-01T23:59:59Z" activateOnCreate: true } }) { ... on PaymentCard { id last4 expirationDate } } }mutation SimulateAuthorization { simulateAuthorization(input: { cardId: "<PAYMENT_CARD_ID>" amount: { value: 4200, currencyCode: USD } }) { ... on AuthorizationEvent { id responseCode } } }
Excerpts — the first step omits some required fields for brevity. Replace every <PLACEHOLDER> and see the API Reference for the full input shape.