{"uid":"cap_l2u3QwlJkvVPAXYOHvuoT","slug":"saylor-innovations-guide-library-x402-payment-failure-debugging-5fdd690e","name":"Saylor Innovations Guide Library: x402 Payment Failure Debugging","description":"Debug a failing x402 payment as a buyer - decode the challenge, balance, expired signatures and safe retry","url":"https://saylorinnovations.com/api/kb/x402-payment-failure-debugging?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"}},"additionalProperties":false},"output":{"type":"object","required":["type"],"properties":{"type":{"type":"string","const":"json"},"example":{"type":"object","required":["id","t","c","body"],"properties":{"c":{"type":"string","description":"Category of the guide"},"t":{"type":"string","description":"Title of the guide"},"id":{"type":"string","description":"Identifier of the record"},"body":{"type":"string","description":"Main body text"},"price":{"type":["number","null"],"description":"Price"},"license":{"type":"string","description":"License identifier"}}}}}}},"responseSchema":null,"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.01","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":"$0.01/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.01","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.01","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_vx57VgLYhW8BfiSXmSugc","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.01","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Returns a guide explaining how to debug failing x402 payments as a buyer, covering challenge decoding, balance issues, expired signatures, and safe retry strategies","exampleAgentPrompt":"My x402 payment keeps failing — can you pull up a guide that walks me through decoding the challenge, figuring out if it's a balance or expired signature issue, and how to safely retry?","exampleUseCases":[{"title":"Debugging an x402 challenge decode error","prompt":"I'm integrating x402 payments and my buyer client keeps throwing a challenge decode error — can you get me a step-by-step debugging guide so I can figure out what's malformed?"},{"title":"Fixing expired x402 signature on retry","prompt":"My x402 payment request failed with what looks like an expired signature. Pull up the debugging guide so I can understand how to safely retry without double-paying."},{"title":"Diagnosing x402 insufficient balance failure","prompt":"I'm getting a payment failure on the buyer side of my x402 integration — I think it might be a balance issue. Can you fetch the x402 payment failure debugging guide so I know what to check?"}],"resultDescription":"A JSON object containing a guide record with fields: id (record identifier), t (title of the guide), c (category), body (full guide text covering challenge decoding, balance checks, expired signature diagnosis, and safe retry procedures), price (optional), and license identifier.","failureModes":["Endpoint returns non-200 if service is unavailable","Payment of $0.01 USDC required via x402 — missing or invalid payment header will result in 402 Payment Required","Guide body may be truncated or unavailable if content has been removed","Network timeout if the service is temporarily degraded"],"whenToPreferThis":"Choose this endpoint when you need structured, human-readable guidance specifically for debugging x402 payment failures from the buyer perspective, including challenge decoding, balance diagnosis, expired signature handling, and retry logic. Prefer this over general web search when you want a curated, authoritative guide returned as structured JSON that an agent can parse and act on.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-21T12:39:35.022Z","isFirstParty":false,"canonicalSlug":"saylor-innovations-guide-library-x402-payment-failure-debugging-5fdd690e"}