{"uid":"cap_j6bpkZMKg3DDpxErdnW53","slug":"maxwell-x402-payment-failure-diagnostics-80ce977b","name":"Maxwell x402 Payment Failure Diagnostics","description":"x402 Doctor: why a payment failed, in plain words: the cause, whose side it is on (your client, your wallet, the network, the seller or the facilitator) and how to fix it, from over 40 named causes (x402 and Coinbase facilitator codes, EVM and Solana, HTTP and network errors). Send the seller 402 as challenge and the error as response, by POST JSON or GET query. Unknown failures are reviewed nightly.","url":"https://api.maxwellinternational.ai/v1/doctor/payment?utm_source=zero.xyz","method":"POST","headers":{},"bodySchema":{"type":"object","$schema":"https://json-schema.org/draft/2020-12/schema","required":["input"],"properties":{"input":{"type":"object","required":["type","method"],"properties":{"body":{"type":"object"},"type":{"type":"string","const":"http"},"method":{"enum":["POST","PUT","PATCH"],"type":"string"},"headers":{"type":"object","additionalProperties":{"type":"string"}},"bodyType":{"enum":["json","form-data","text"],"type":"string"}},"additionalProperties":false},"output":{"type":"object","required":["type"],"properties":{"type":{"type":"string"},"example":{"type":"object"}}}}},"responseSchema":{"type":"json","example":{"verdict":"client_problem"}},"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_eDUO9ek65W8DcrIo_gOLX","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":"Diagnoses why an x402 payment failed and identifies which party is responsible (client, wallet, network, or seller), returning a plain-language verdict.","exampleAgentPrompt":"I got a 402 payment failure when trying to call a seller endpoint — can you diagnose why it failed and tell me whose fault it is, using the 402 challenge and the error response I received?","exampleUseCases":[{"title":"Debugging a failed agent payment","prompt":"My AI agent tried to pay a seller using x402 but got rejected. Here's the 402 challenge the seller sent and the error I got back — can you tell me why it failed and whether it's my wallet's problem, the client's, the network's, or the seller's?"},{"title":"Seller troubleshooting payment rejections","prompt":"I'm a seller and buyers keep getting payment errors on my endpoint. Can you look at the 402 challenge I'm sending and the error they receive, and tell me if the problem is on my side or theirs?"},{"title":"Automated payment pipeline diagnostics","prompt":"My automated payment pipeline is failing on certain x402 transactions. I have the 402 header challenge and the error response — please diagnose the failure and categorize whether it's a client problem, wallet issue, network error, or a seller configuration problem."}],"resultDescription":"A JSON object with a 'verdict' field containing a plain-language classification of the failure (e.g. 'client_problem') indicating which party — client, wallet, network, or seller — is responsible for the payment failure, along with an explanation of what went wrong.","failureModes":["Missing or malformed 'type' or 'method' fields in input returns a validation error","Unsupported HTTP method (not GET, HEAD, or DELETE) causes schema rejection","Providing incomplete or corrupted 402 challenge headers may yield an inconclusive verdict","Network timeouts when the endpoint is unreachable"],"whenToPreferThis":"Use this endpoint when an x402 payment has failed and you need a human-readable explanation of why, and to determine which party (client, wallet, network, or seller) is at fault — without making any actual payment. Prefer this over manual debugging when you need quick, automated root-cause classification in an agent workflow.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-02T04:48:56.476Z","isFirstParty":false,"canonicalSlug":"maxwell-x402-payment-failure-diagnostics-80ce977b"}