National Bank of Belarus API
Live official exchange-rate data from the National Bank of the Republic of Belarus (NBRB), the central bank of Belarus, for the Belarusian rouble (BYN): the NBRB official rate for every published currency (normalised to one unit), a single currency's rouble-per-unit rate and inverse, the daily time series of a currency's official rate over a full date range, and currency conversion between any two published currencies (including BYN) cross-computed through the rouble at NBRB rates.
api.oanor.com/nbrb-api