{"success":true,"preview":true,"preview_truncated":true,"preview_mode":"live_contract_proof","preview_note":"The live source completed successfully. This preview shows the request and paid response shape, but withholds decision-ready values. Purchase once to receive the complete current result.","live_proof":{"source":"https://www.exchangerate-api.com","fetched_at":"2026-09-17T12:48:38.134Z","data_mode":"live_source","top_level_fields":["success","source","source_url","base","updated_at","next_update_at","rates"],"response_shape":{"type":"object","fields":{"success":{"type":"boolean"},"source":{"type":"string"},"source_url":{"type":"string"},"base":{"type":"string"},"updated_at":{"type":"string"},"next_update_at":{"type":"string"},"rates":{"type":"object","fields":{"USD":{"type":"number"}},"fields_truncated":false}},"fields_truncated":false}},"request":{"method":"GET","path":"/api/v1/fx_rates","parameters":{"base":"EUR","target":"USD"}},"purchase":{"price_usdc":"0.02","method":"GET","url":"https://ai-data-marketplace-1042299154756.us-central1.run.app/api/v1/fx_rates","protocol":"x402 v2 exact, USDC on Base mainnet","how":"Repeat this request without preview=true, read the PAYMENT-REQUIRED header, sign it, and retry with PAYMENT-SIGNATURE."},"marketplace_metadata":{"data_mode":"live_source","billable":true,"availability":"operational","source":"ExchangeRate-API open endpoint"}}