{"uid":"cap_03PPOYtxuzvyd8fFAE3fY","slug":"numberintel-dev-x402-settlement-attestation-f0f5deca","name":"numberintel.dev x402 Settlement Attestation","description":"Signed settlement attestation: we make a REAL x402 purchase from your target endpoint (up to $0.1), grade the delivered response against its advertised schema, and return an EIP-191-signed attestation embedding the on-chain USDC receipt. Proof-of-real-delivery for directories, reputation systems and sellers.","url":"https://numberintel.dev/v1/attest?utm_source=zero.xyz","method":"POST","headers":{},"bodySchema":{"type":"object","properties":{"body":{"type":"object","description":"JSON body for POST targets"},"method":{"type":"string","description":"GET or POST"},"target":{"type":"string","description":"https URL of the x402 endpoint to buy from"},"max_spend_usd":{"type":"number","description":"cap on target spend, hard max 0.1"}}},"responseSchema":{"type":"json","example":{"signature":"0x...","attestation":{"id":"a1b2c3d4e5f60718","grade":"delivered","target":"https://api.example.com/v1/data","version":1,"attestor":"0x3708...9234","delivery":{"sha256":"...","is_json":true,"http_status":200,"paid_latency_ms":900,"schema_match_ratio":1},"purchase":{"receipt":{"network":"eip155:8453","transaction":"0x..."},"settled":true,"quote_usd":0.01}}}},"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.25","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":"$0.25/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.25","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.25","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_NrweHx2bokT03_DzRf8Zf","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.25","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Acts as an x402 payment proxy that purchases a target API endpoint on the caller's behalf and returns a cryptographically signed attestation of delivery, settlement, and response quality.","exampleAgentPrompt":"Call the x402 phone intelligence endpoint at https://numberintel.dev/v1/lookup for me, cap the spend at $0.05, and bring back a signed attestation proving it was paid and delivered correctly.","exampleUseCases":[{"title":"Audit trail for paid API calls","prompt":"I need a verifiable receipt proving that the x402 endpoint at https://api.example.com/v1/data was successfully called, paid in USDC, and returned a valid JSON response — cap the spend at $0.05 and give me the signed attestation."},{"title":"Agent-to-agent x402 payment verification","prompt":"My agent just attempted a pay-per-call to https://numberintel.dev/v1/lookup — can you proxy that call with a max spend of $0.10 and return a cryptographic attestation I can show to prove settlement happened on Base?"},{"title":"Schema compliance check for paid API response","prompt":"Hit the x402 endpoint at https://data.example.com/v1/records with a POST and body {\"query\":\"test\"}, cap the spend at $0.08, and tell me the schema match ratio and delivery grade from the attestation."}],"resultDescription":"Returns a JSON object containing a hex signature from the attestor, and a nested attestation object with: a unique attestation ID, a delivery grade (e.g. 'delivered'), the target URL, attestor address, delivery details (SHA-256 hash of response, is_json flag, HTTP status, paid latency in ms, schema match ratio), and purchase details including the on-chain transaction hash on Base (eip155:8453), settlement status, and the quoted USD cost.","failureModes":["Target URL unreachable or returns non-2xx before payment: attestation grade may reflect failure","max_spend_usd exceeded by target price: call aborted before payment","Invalid or non-x402 target URL: request rejected with error","Insufficient USDC balance for x402 settlement: payment fails","Target endpoint schema mismatch: low schema_match_ratio in attestation but call may still be graded delivered","Network congestion on Base causing settlement delays"],"whenToPreferThis":"Choose this endpoint when you need a cryptographically signed, on-chain proof that a specific x402 pay-per-call API was successfully purchased, called, and delivered a valid response. It is ideal for audit trails, agent-to-agent trust, or compliance scenarios where proving payment and delivery happened is as important as the data itself. Prefer it over raw x402 calls when the consumer needs an attestor-signed receipt rather than just the raw API response.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-02T04:34:39.503Z","isFirstParty":false,"canonicalSlug":"numberintel-dev-x402-settlement-attestation-f0f5deca"}