I built this actor; it's a paid tool on Apify with a free trial credit. Most "free currency API" results want a key, cap your requests, and don't say where their numbers come from. For accounting that last part matters: VAT and bookkeeping rules often name a specific central bank's rate for a specific day. In Poland, for example, you convert a foreign-currency invoice at the NBP average rate from the last business day before the invoice date. Central banks publish these rates for free,...