{"uid":"cap_YKITpXnru1CILMjTeyhDe","slug":"x402-base-tools-eip-3009-authorization-status-check-88091352","name":"x402 Base Tools – EIP-3009 Authorization Status Check","description":"Base mainnet data for agents, read live from the chain and paid per call in USDC: gas prices and costs, token prices from Uniswap and Aerodrome pools, balances, token info, transaction decoding, x402 payment checks, EIP-3009 authorization status, Basenames and address profiles. Lookups of things that do not exist are not charged.","url":"https://wt7tysfcmjm8fpzl.68r.lambda-web.us-east-1.on.aws/v1/authorization?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":["authorizer","nonce"],"properties":{"nonce":{"type":"string","description":"the authorization nonce (0x + 64 hex digits)"},"authorizer":{"type":"string","description":"the paying wallet (0x...)"}}}},"additionalProperties":false},"output":{"type":"object","required":["type"],"properties":{"type":{"type":"string"},"example":{"type":"object","properties":{"used":{},"usdc_balance":{}}}}}}},"responseSchema":{"type":"json","example":{"used":false,"usdc_balance":"2.89"}},"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.001","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":"$0.001/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.001","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.001","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_AypiOSpzkJ85irNgtZ_Mt","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.001","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Checks whether a specific EIP-3009 authorization nonce has been used and returns the authorizer's USDC balance on Base mainnet","exampleAgentPrompt":"Check if the EIP-3009 authorization nonce 0x3a1b2c... has already been used for wallet 0xAbCd... on Base, and tell me the wallet's current USDC balance.","exampleUseCases":[{"title":"Prevent double-spend before payment relay","prompt":"Before I relay this signed USDC authorization, check if nonce 0x4f8e2a1b3c7d9e0f1a2b3c4d5e6f7a8b9c0d1e2f3a4b5c6d7e8f9a0b1c2d3e4f has already been used for wallet 0x1234567890abcdef1234567890abcdef12345678 on Base."},{"title":"Verify x402 payment authorization is still valid","prompt":"An agent just submitted an x402 payment request — can you verify that authorization nonce 0xaabbccddeeff00112233445566778899aabbccddeeff00112233445566778899aa for authorizer 0xDeAdBeEf0000000000000000000000000000dEaD hasn't been spent yet and they have enough USDC?"},{"title":"Audit wallet USDC balance and nonce state","prompt":"I need to audit this wallet — check if nonce 0x0011223344556677889900aabbccddeeff0011223344556677889900aabbccdd is still unused and what USDC balance wallet 0x9999888877776666555544443333222211110000 currently holds on Base mainnet."}],"resultDescription":"Returns a JSON object with 'used' (boolean indicating whether the authorization nonce has already been consumed) and 'usdc_balance' (string representing the authorizer's current USDC balance on Base, e.g. '2.89'). If the authorization or wallet does not exist, the call is not charged.","failureModes":["Invalid nonce format (not 0x + 64 hex digits) returns an error","Invalid authorizer address format returns an error","RPC or chain read failure may return a 5xx error","Non-existent nonce/authorizer returns result without charge but may return null/default values"],"whenToPreferThis":"Use this endpoint when you need to verify EIP-3009 USDC authorization status on Base mainnet before relaying a signed meta-transaction, or when you need to check a wallet's live USDC balance alongside nonce validity. Prefer this over generic RPC calls when you want pay-per-use pricing with no infrastructure setup, and when you need both nonce status and balance in a single call. Ideal for x402-enabled agent payment workflows on Base.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-30T12:31:24.888Z","isFirstParty":false,"canonicalSlug":"x402-base-tools-eip-3009-authorization-status-check-88091352"}