{"uid":"cap_wm5R8x3RgzJ2pJ1MNuo4I","slug":"x402-preflight-5543495b","name":"x402 Preflight","description":"Check an x402 seller before you pay it. Probes the endpoint now, checks that its payment can actually succeed (token EIP-712 domain, payTo), and adds its 30-day uptime from our monitor of paid Bazaar listings, how many distinct buyers paid it, and how its price compares with similar listings, with cheaper well-used alternatives. Returns a verdict (ok, caution, avoid) with the reasons.","url":"https://f0r6bcvc1s410hk1.68r.lambda-web.us-east-1.on.aws/v1/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":["url"],"properties":{"url":{"type":"string","maxLength":2048,"description":"https URL of the x402 endpoint you are about to pay"},"method":{"enum":["GET","POST"],"type":"string","description":"method you will call it with (default GET)"},"max_price_usd":{"type":"number","description":"the most you are willing to pay per call; a higher price gives the verdict avoid"}}}},"additionalProperties":false},"output":{"type":"object","required":["type"],"properties":{"type":{"type":"string"},"example":{"type":"object","required":["url","verdict","reasons"],"properties":{"now":{"type":"object","description":"the live probe: method, status, latency, protocol version, price, networks, payTo"},"url":{"type":"string"},"bazaar":{"type":"object","description":"the CDP Bazaar listing: distinct payers and calls in 30 days"},"market":{"type":"object","description":"median price of similar listings and cheaper alternatives with payers and uptime"},"history":{"type":"object","description":"our monitor's 30-day record: probes, uptime (0-1), median latency, last failure, price changes; null when not monitored"},"reasons":{"type":"array","description":"why the verdict is not ok; empty when it is"},"verdict":{"enum":["ok","caution","avoid"],"type":"string"}}}}}}},"responseSchema":{"type":"json","example":{"now":{"ms":180,"method":"GET","pay_to":"0x...","status":402,"networks":["eip155:8453"],"price_usd":0.01,"x402_version":2},"url":"https://api.example/v1/search","bazaar":{"listed":true,"calls_30d":3,"payers_30d":1,"last_called_at":"2026-10-20T08:00:00Z"},"market":{"query":"Web search for agents","alternatives":[{"resource":"https://other.example/search","price_usd":0.002,"payers_30d":40,"uptime_30d":1}],"median_price_usd":0.005,"similar_listings":20},"history":{"probes":120,"uptime":0.99,"median_ms":210,"last_ok_at":"2026-10-25T00:00:00Z","last_failure":null,"price_changes":[],"monitored_since":"2026-10-01T00:00:00Z"},"reasons":["Only 1 distinct buyer paid it in the last 30 days."],"verdict":"caution"}},"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.002","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":"$0.002/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.002","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.002","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_Z4C0EibqX6GWUZBG-HuoF","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.002","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Probes an x402 paywall endpoint before payment to return a trust verdict (ok/caution/avoid) with uptime, buyer count, price comparison, and payment validity checks.","exampleAgentPrompt":"Before I pay that x402 search endpoint at https://api.example.com/v1/search, check whether it's trustworthy — probe it live, see how many buyers have paid it in the last 30 days, and tell me if there are cheaper alternatives I should use instead.","exampleUseCases":[{"title":"Vet unknown x402 seller before paying","prompt":"I found an x402 API at https://data.somevendor.io/v1/prices that costs $0.05 per call — before I pay it, can you check if it's legit, how many people have actually paid it, and whether there's a cheaper option that does the same thing?"},{"title":"Enforce max price policy on x402 calls","prompt":"My budget cap is $0.01 per call — run a preflight on https://tools.example.com/v1/translate and give me a verdict; if it costs more than that, mark it as avoid and show me what cheaper alternatives exist."},{"title":"Audit x402 endpoint uptime before integration","prompt":"We're about to integrate https://api.partnerco.com/v1/summary into our pipeline — can you do a preflight check to see its 30-day uptime, median latency, and whether any payment issues have been flagged?"}],"resultDescription":"A JSON object containing: a live probe result (status, latency, payTo address, price, networks, x402 protocol version), a verdict of 'ok', 'caution', or 'avoid' with a list of reasons, Bazaar listing data (distinct payers and calls in 30 days), 30-day uptime history (probes, uptime ratio, median latency, last failure, price changes), and market context (median price of similar listings and cheaper well-used alternatives).","failureModes":["Endpoint URL is unreachable or returns non-402 status — live probe fails with no payment info returned","Endpoint not listed on Bazaar — bazaar field will be null or show listed:false, limiting social proof data","No monitoring history available — history field returns null if the endpoint has never been monitored","Invalid or missing URL query parameter — API returns a validation error","Endpoint returns malformed x402 payment headers — preflight flags it as avoid with a reason explaining the parsing failure"],"whenToPreferThis":"Use this endpoint when an AI agent is about to call an x402-gated API and needs to verify payment safety, check real-world usage evidence, compare price against alternatives, or enforce a maximum price budget before committing any funds. It is the right choice whenever you want a second opinion on an unknown x402 seller, need uptime data for reliability decisions, or want to discover cheaper equivalent services before paying.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-29T12:33:05.389Z","isFirstParty":false,"canonicalSlug":"x402-preflight-5543495b"}