DeFi market-data feed: perp open interest, funding rate, mark price and a directional signal across top assets (BTC/ETH/SOL/…), plus optional per-asset verdict. Deterministic, Ed25519-signed. 0.002 USDC via x402 on Base. SYNTHORA. First 3 calls FREE per wallet — send header 'X-WALLET: 0x<your Base address>' (no payment); after that per call.