balance is the amount currently available to spend on the card, separate from the business USD card-wallet balance. This response does not contain the full card number or CVV; use the explicit Reveal Card Details endpoint when the cardholder needs them.
Test and live API keys use the same base URL, https://api.usenumero.com/numeroaccount/api/v1. A test_key_ returns isolated simulated card data; a live key reads the business’s live cards. Use a reference from the matching mode.
nameOnCard is the exact issuer-returned card name, which can differ from the customer’s full legal name. label remains the separate merchant-defined label. billingAddress contains address, city, state, postalCode and country when supplied by the issuer; use this address for card billing, not the cardholder’s residential address. Missing metadata is returned as null, not guessed. Opening an existing card refreshes issuer metadata, which is then available in card-list responses too.
Card endpoints use the same base URL and API key as the rest of the API, and are signature-gated: sendX-Numero-SignatureandX-Numero-Signature-Version: v2as well. See Request signing.