{"uid":"cap_l701tjUXgvcEhBE8QVdP6","slug":"numberintel-dev-x402-preflight-attestation-e8f0e039","name":"numberintel.dev x402 Preflight Attestation","description":"x402 conformance preflight of any endpoint: parses the 402 envelope, lints accepts[] (atomic units, payTo, network), reports the quote, Bazaar extension presence and problems. No purchase is made.","url":"https://numberintel.dev/v1/attest/preflight?utm_source=zero.xyz","method":"GET","headers":{},"bodySchema":{"type":"object","$schema":"https://json-schema.org/draft/2020-12/schema","required":["input"],"properties":{"input":{"type":"object","required":["type","method"],"properties":{"type":{"type":"string","const":"http"},"method":{"enum":["GET"],"type":"string"},"queryParams":{"type":"object","required":["target"],"properties":{"method":{"type":"string","description":"GET or POST, default GET"},"target":{"type":"string","description":"https URL of the x402 endpoint to check"}}}},"additionalProperties":false},"output":{"type":"object","required":["type"],"properties":{"type":{"type":"string"},"example":{"type":"object"}}}}},"responseSchema":{"type":"json","example":{"grade":"quote_ok","quote":{"usd":0.01,"payTo":"0x...","network":"eip155:8453"},"target":"https://api.example.com/v1/data","problems":[],"reachable":true,"http_status":402,"x402_version":2,"accepts_count":1,"base_mainnet_option":true,"has_bazaar_extension":true}},"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.02","displayCostAsset":"USDC","priceDynamic":false,"priceHint":null,"priceStatus":"priced","priceSource":"probe","requiresHandshake":false,"reviewCount":0,"rating":{"score":"0.00","successRate":"0.00","reviews":0,"stars":null,"state":"unrated"},"availabilityStatus":"unknown","priceObserved":null,"sessionDeposit":null,"pricing":{"kind":"static","summary":"$0.02/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.02","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.02","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_nC7XxgmXDI4F_0v7Alpor","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.02","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Checks whether a target x402-enabled HTTP endpoint is reachable, properly configured, and returns a quote for its payment requirements before committing to a paid call.","exampleAgentPrompt":"Before I call that paid API, can you preflight check https://api.example.com/v1/data to confirm it's reachable, returning a 402 with a valid x402 quote, and tell me how much it costs and what address to pay?","exampleUseCases":[{"title":"Pre-call payment quote check","prompt":"I want to call https://some-data-api.com/v1/records but I'm not sure how much it charges or if its x402 setup is valid — can you preflight that URL and tell me the USD price, payTo address, and network before I commit?"},{"title":"Diagnosing a broken x402 endpoint","prompt":"My API at https://myservice.dev/v1/prices is supposed to accept x402 payments but clients are complaining it's not working — can you run a preflight attestation on it and tell me what problems it finds?"},{"title":"Confirming Bazaar extension support","prompt":"Can you check https://thirdparty-api.io/v1/lookup and verify whether it has the Bazaar extension enabled and is on Base mainnet, and give me its x402 version and grade?"}],"resultDescription":"Returns a JSON object with a grade (e.g. 'quote_ok'), the payment quote including USD price, payTo address, and network, whether the endpoint is reachable, the HTTP status code, x402 version, number of accepted payment options, whether a Base mainnet option exists, whether the Bazaar extension is present, and a list of any detected problems.","failureModes":["Target URL unreachable — reachable: false with empty quote and non-empty problems list","Target does not return HTTP 402 — grade reflects non-conformant status","Malformed x402 response at target — problems list populated with parse errors","Missing required query parameter 'target' — 400 Bad Request","Payment not settled for this preflight call itself — 402 returned by the preflight endpoint","Network timeout on target URL — reachable: false"],"whenToPreferThis":"Use this endpoint when you need to validate or audit an x402-gated API before making a live paid call — especially to confirm price, payment address, network, and x402 protocol version without spending funds. Prefer it over blindly calling a pay-per-use endpoint when you want to surface configuration problems, confirm Bazaar extension support, or let a user review costs before authorizing payment.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-02T04:33:48.465Z","isFirstParty":false,"canonicalSlug":"numberintel-dev-x402-preflight-attestation-e8f0e039"}