Realized volatility for 16 crypto assets (BTC/ETH/SOL/BNB/XRP/DOGE/ADA/AVAX/LINK/DOT/LTC/TRX/BCH/ATOM/NEAR/APT): 7-day, 30-day, and 90-day annualized realized vol using three estimators (close-to-close, Parkinson, Garman-Klass) from Binance daily OHLC closed candles only. Essential for risk management, position sizing, and options pricing. Pay-per-call via x402.