SOL/USD tip read from Solana state, no CEX or key: median of the Pyth SOL/USD push-feed account and Orca's two deepest SOL/USDC whirlpools (one getMultipleAccounts call), with spread in bps, refreshed every 2 s. Long-poll with ?since=<seq>&wait=25. Prepaid meter price $0.0002/call (packs at /v1/meter); SSE at /v1/stream/tips.