Hello!
https://api.xbts.io/ - API for assets with the XBTSX ticker i.e. for UIA assets. This API is used for Market Caps. This API does not display the price for BitUSD. Sometimes, as part of a partnership, we add assets that are created on BitShares to our API, for example, this is now working for EVRAZ, BEOS, YOYOW, so that these coins receive statistics for Market Caps. You just wrote about XBTSX.USD - this asset is used by users to exchange for fiat USD and withdrawal to Payeer for withdrawal to cards. The price of this asset is determined by demand-based traders. In the future, we plan to increase the liquidity of this asset to ensure a more stable price. What can you do to get the price on BitUSD - install the blockchain and get the price from the blockchain.