{"uid":"cap_fuy8SkT2E6Fk9_hs3Vhdg","slug":"base-onchain-data-address-type-contract-metadata-4a35ed3b","name":"Base Onchain Data – Address Type & Contract Metadata","description":"Pay-per-call data for AI agents, paid in USDC on Base with x402: token risk checks (rug check) on Base, Ethereum, Arbitrum, Optimism, Polygon and Solana, onchain reads (balances, transactions, gas, contracts, NFTs, whale trades, new pools, ENS and Basenames), ECB exchange rates, and Canadian sales tax and business days.","url":"https://ca-tax-api-mainnet.lxtap.workers.dev/base/contract?utm_source=zero.xyz","method":"GET","headers":{},"bodySchema":{"type":"object","$schema":"https://json-schema.org/draft/2020-12/schema","required":["input"],"properties":{"input":{"type":"object","required":["type","method"],"properties":{"type":{"type":"string","const":"http"},"method":{"enum":["GET"],"type":"string"},"queryParams":{"type":"object","required":["address"],"properties":{"address":{"type":"string","pattern":"^0x[0-9a-fA-F]{40}$","description":"Any address on Base"}},"additionalProperties":false}},"additionalProperties":false},"output":{"type":"object","required":["type"],"properties":{"type":{"type":"string"},"example":{"type":"object"}}}}},"responseSchema":{"type":"json","example":{"kind":"ERC-20 token","name":"USD Coin","chain":"base","proxy":{"admin":"0x4fc7850364958d97B4d3f5A08f79db2493f8cA44","upgradeable":true,"implementation":"0x2Ce6311ddAE708829bc0784C967b7d77D19FD779"},"symbol":"USDC","address":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","decimals":6,"standards":{"erc20":true,"erc165":false,"erc721":false,"erc1155":false},"isContract":true,"totalSupply":"4291989037.45169","bytecodeBytes":1852,"nativeBalance":"0.009800646158085843"}},"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_fvDAaQfyxA4Vxgzqyg1ig","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":"Identifies whether a Base address is a wallet (EOA) or contract, and returns token standard, name, symbol, proxy details, bytecode size, nonce, and ETH balance.","exampleAgentPrompt":"Can you look up what's at Base address 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 — is it a wallet or a contract, what token standard does it use, and what's its name and symbol?","exampleUseCases":[{"title":"Identify NFT collection contract on Base","prompt":"I have this Base address 0xd9aAEc86B65D86f6A7B5B1b0c42FFA531710b6CA — can you tell me if it's a contract, what token standard it implements, and its name and symbol?"},{"title":"Check if address is EOA or smart contract","prompt":"Is the Base address 0x4200000000000000000000000000000000000006 a regular wallet or a smart contract? If it's a contract, what's its bytecode size and ETH balance?"},{"title":"Inspect upgradeable proxy on Base","prompt":"Look up the Base address 0x2Ae3F1Ec7F1F5012CFEab0185bfc7aa3cf0DEc22 and tell me if it's an upgradeable proxy — I need to know the implementation address and who the admin is."}],"resultDescription":"Returns whether the address is an EOA or contract, the token standard it implements (ERC-20, ERC-721, ERC-1155, or none), the token name and symbol, proxy implementation and admin addresses if applicable, bytecode size in bytes, the address nonce, and current ETH balance.","failureModes":["Invalid address format (not a valid 0x-prefixed 40-hex-char address) returns a validation error","Address not found or network error returns an API error","Contract does not implement a recognized token standard — token fields returned as null or empty","RPC/node timeout causes delayed or failed response","Newly deployed contract may have incomplete or missing metadata"],"whenToPreferThis":"Use this endpoint when you need to classify a Base network address and retrieve rich contract metadata in a single call — especially when you need token standard, proxy details, and balance together. Prefer this over general blockchain explorers when building automated agents that need structured, machine-readable onchain data for Base specifically. Choose this over the Ethereum or OP Mainnet equivalents when the target address is on the Base L2 network.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-23T12:45:22.098Z","isFirstParty":false,"canonicalSlug":"base-onchain-data-address-type-contract-metadata-4a35ed3b"}