Watch the crypto market for 24 hours: up to 10 conditions (price, % change, funding, open interest, liquidations, order book, Fear and Greed, whale orders, news impact), checked every minute; when one happens you get a signed webhook and it shows in the watch's status. Costs USD 0.02, paid with x402 (USDC on Base); a request that fails is not charged. Keep the returned secret: watch_status and stop_watch need it.