{"uid":"cap_tKGVKjQnfB7PPS_VsEMs4","slug":"base-token-facts-api-wallet-lookup-43869d26","name":"Base Token Facts API – Wallet Lookup","description":"Get ETH and USDC balance for a wallet address","url":"https://base-facts.yankii.fr/v1/wallet?utm_source=zero.xyz","method":"POST","headers":{},"bodySchema":{"type":"object","properties":{"address":{"type":"string","description":"0x-prefixed address"}}},"responseSchema":{"type":"json","example":{"eth":{"wei":"0","decimal":"0.0"},"usdc":{"atomic":"0","decimal":"0.000000"},"nonce":0,"source":"base-mainnet-rpc","isContract":false,"blockNumber":"52130000"}},"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_iZUn2ZNS3XZgnW0yG9p7n","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":"Returns on-chain ETH balance, USDC balance, nonce, contract status, and current block number for a given Base mainnet wallet address.","exampleAgentPrompt":"What's the ETH and USDC balance for wallet 0x1234...abcd on Base mainnet, and is it a smart contract?","exampleUseCases":[{"title":"DeFi bot pre-flight balance check","prompt":"Before executing a swap, check whether wallet 0xDeAdBeEf...1234 on Base has enough ETH and USDC, and tell me its current nonce."},{"title":"Fraud detection contract screening","prompt":"Is the address 0xAbCd...5678 a smart contract or a regular wallet on Base mainnet? I need to know before sending funds."},{"title":"Portfolio dashboard balance sync","prompt":"Pull the current ETH and USDC balances for 0x9999...aaaa on Base and tell me what block number those figures are from."}],"resultDescription":"A JSON object containing the wallet's ETH balance in both wei and human-readable decimal, USDC balance in atomic units and decimal, the account nonce, a boolean indicating whether the address is a contract, the block number at which the data was fetched, and the RPC source identifier (base-mainnet-rpc).","failureModes":["Invalid or malformed address (not 0x-prefixed or wrong length) — likely returns a 400 or error JSON","Address not found on Base mainnet — returns zero balances and nonce 0","RPC node unavailable or timeout — may return 5xx or connection error","Network congestion causing stale block number data","Payment failure via x402 protocol — 402 response if USDC payment not completed"],"whenToPreferThis":"Use this endpoint when you need a quick, atomic snapshot of a Base mainnet wallet's ETH and USDC balances plus contract status in a single call, without running your own RPC node. Prefer it over general Ethereum RPC calls when you specifically need Base-chain data with a pay-per-call micropayment model via x402.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-11T00:38:39.872Z","isFirstParty":false,"canonicalSlug":"base-token-facts-api-wallet-lookup-43869d26"}