Currency for displayed prices.
Property's own currency is the first choice and matches Booking's own picker: prices come back in whatever the property quotes in — MYR in Kuala Lumpur, THB in Bangkok — with no conversion. Every row states its own currency, so you always know which you got.
Otherwise pick one of 147 currencies. That is every ISO-4217 code Booking honours on this surface, established by requesting a property once per code and reading back the currency it priced in, with bogus codes as the control.
The nine it refuses are ERN, FKP, GIP, KPW, SHP, SLE, TMT, VED and ZWG. They are refused outright rather than falling back silently, so you cannot ask for one by accident.
Booking's app only offers 49 of the 147 in its own menu, and its exchange-rate table lists 188 — including pre-euro currencies and gold. The 147 here is the set measured to actually price a room.
Every price in a row follows this setting, including the cancellation ladder and the prepayment schedule. One documented exception: details.damageDeposit.amount stays in the property's own currency, because a deposit is collected at the desk in local money — its currency says so.
Options:HOTELUSDEURGBPAUDCADCHFCNYJPYINRBRLMXNSEKNOKDKKPLNAEDSGDZARTRYRUBAFNALLAMDANGAOAARSAWGAZNBAMBBDBDTBGNBHDBIFBMDBNDBOBBSDBTNBWPBYNBZDCDFCLPCOPCRCCUPCVECZKDJFDOPDZDEGPETBFJDGELGHSGMDGNFGTQGYDHKDHNLHTGHUFIDRILSIQDIRRISKJMDJODKESKGSKHRKMFKRWKWDKYDKZTLAKLBPLKRLRDLSLLYDMADMDLMGAMKDMMKMNTMOPMRUMURMVRMWKMYRMZNNADNGNNIONPRNZDOMRPABPENPGKPHPPKRPYGQARRONRSDRWFSARSBDSCRSDGSOSSRDSSPSTNSVCSYPSZLTHBTJSTNDTOPTTDTWDTZSUAHUGXUYUUZSVESVNDVUVWSTXAFXCDXOFXPFYERZMW