Use Check for a changed/unchanged signal and optional compact text diff. Exactly one URL or existing watch ID; URL plus rules can create a watch, whereas watch_id reuses saved rules and forbids overrides. Use Smart Diff for structured changes. On-demand only; x402 $0.005 USDC on Base, including cache hits.
Api EndpointInfrastructureReachable · 369 ms0.005 USDC0.005 USDC · eip155:8453 · USDC
https://fresh402.kirilllabs.workers.dev/v1/check