Current Bitcoin (BTC) spot price in USD, EUR, GBP, CAD, CHF, AUD and JPY, averaged across major exchanges, with the number of satoshis per US dollar and the time of the price. Use to convert between sats and fiat, to value a Bitcoin or Lightning payment, or to check the BTC price before a trade. Price $0.003/call via x402 USDC or a card key (/credits), first 25 free; failed calls free. Reads or computes only; not marked read-only because each call is charged.