Currency Codes (ISO 4217) API
The ISO 4217 currency-code register as an API — not foreign-exchange rates, but the metadata a checkout or accounting system needs to handle money correctly. Each currency carries its 3-letter alphabetic code, 3-digit numeric code, official name, the number of minor units (decimal places, e.g. JPY 0, USD 2, BHD 3) and the list of countries that use it. Look a currency up by alphabetic or numeric code, find the currencies a country uses, search by name, or list the whole register. Bundled and served from memory — always fast, no key needed upstream.
api.oanor.com/currencycodes-api