{"uid":"cap_DXhk1teWhg43OrZb7yUbC","slug":"realx402-seller-754e839e","name":"realx402-seller","description":"Verify an x402 seller before paying it: does it exist and respond with a well-formed 402 challenge, is its own declared input/output schema internally consistent, and is its payout address sanctioned? Checked live against the seller itself plus Chainalysis's sanctions oracle and Blockscout (Base payTo addresses only). Confirms the checkable things about a seller check out -- not a guarantee of trustworthiness, which no free source can promise.","url":"https://goodsong.dev/verify/seller","method":"POST","headers":{},"bodySchema":{"type":"object","properties":{"method":{"enum":["GET","POST"],"type":"string","description":"HTTP method that triggers the seller's 402 challenge."},"resource_url":{"type":"string","description":"The x402 resource URL to verify."}}},"responseSchema":null,"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.005","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":"$0.005/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.005","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.005","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_W3IiXZL14yAvRoIpkqiOG","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.005","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Verifies an x402 seller endpoint by checking it responds with a valid 402 challenge, validates its schema consistency, and screens its payout address against sanctions oracles","exampleAgentPrompt":"Before we pay that x402 seller at https://api.example.com/data using a POST request, can you run a verification check to make sure its 402 challenge is well-formed, its schema is internally consistent, and its payout address isn't sanctioned?","exampleUseCases":[{"title":"Pre-payment seller due diligence","prompt":"I'm about to have my agent pay an x402 endpoint at https://feeds.example.com/market-data using GET — can you verify it first to make sure the 402 challenge looks legitimate and the payout wallet isn't on any sanctions list?"},{"title":"Vetting a newly discovered x402 API","prompt":"I found an x402 API at https://newprovider.io/transcribe that says it accepts POST requests — can you check whether it actually returns a proper 402 challenge, its declared schema makes sense, and its Base payout address is clean before I wire it into my pipeline?"},{"title":"Automated agent payment safety gate","prompt":"Before my agent pays any x402 seller it discovers, I want it to screen each one — starting with https://data.thirdparty.xyz/weather via GET — to confirm the 402 response is well-formed and the payout address passes sanctions checks."}],"resultDescription":"Returns a structured verification report indicating whether the seller URL responds with a valid 402 challenge, whether the seller's declared input/output schema is internally consistent, and whether the payout address (for Base network) appears on sanctions lists via Chainalysis and Blockscout. Confirms what is mechanically checkable — not a guarantee of full trustworthiness.","failureModes":["Seller URL does not exist or is unreachable — verification fails with connectivity error","Seller returns a non-402 response — challenge validity check fails","Payout address is not a Base network address — sanctions check may be skipped or limited","Schema inconsistency detected — reported but not necessarily blocking","Chainalysis or Blockscout oracle temporarily unavailable — sanctions check may be inconclusive","Malformed or missing input parameters — returns validation error"],"whenToPreferThis":"Choose this endpoint when an AI agent needs to perform pre-payment due diligence on an x402 seller, especially when integrating new or untrusted x402 APIs into an automated payment pipeline. It is the right tool when you need both protocol-level validation (well-formed 402 challenge, schema consistency) and compliance screening (sanctions check on payout address) in a single call. Prefer it over manual inspection or generic URL checkers when the seller uses the x402 payment protocol on Base.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-14T00:30:41.169Z","isFirstParty":false}