Represents Card data in the PaymentMethods API.

Inttegro decodes API responses into this struct. Required fields are always present; optional fields are nil when they do not apply or were not returned. Follow the linked types in t/0 for nested domain values.

Saves and manages customer-owned payment methods.

A payment method always belongs to its attached customer. Tokenization may start a verification flow; inspect the returned verification state before attempting a charge. The API returns masked or provider-safe details and never returns raw reusable credentials.