{"uid":"cap_oLaKQcAqya96rB29LbkWQ","slug":"base-is-contract-checker-2e59f779","name":"Base Is-Contract Checker","description":"Check whether a 0x address on Base is a smart contract or a plain wallet: bytecode size, and whether it is an EIP-1167 minimal proxy and which implementation it points to. Use before sending funds or approving a spender; for a fuller risk verdict use check_counterparty. A malformed address is rejected with 400, uncharged.","url":"https://agent-data-tools.revmesh2074.workers.dev/base/is-contract?utm_source=zero.xyz","method":"GET","headers":{},"bodySchema":{"type":"object","$schema":"https://json-schema.org/draft/2020-12/schema","required":["input"],"properties":{"input":{"type":"object","required":["type","method"],"properties":{"type":{"type":"string","const":"http"},"method":{"enum":["GET"],"type":"string"},"queryParams":{"type":"object","required":["address"],"properties":{"address":{"type":"string","pattern":"^0x[0-9a-fA-F]{40}$","examples":["0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913"],"description":"0x address"}}}},"additionalProperties":false},"output":{"type":"object","required":["type"],"properties":{"type":{"type":"string"},"example":{"type":"object","properties":{"chain":{"type":"string"},"address":{"type":"string"},"chainId":{"type":"number"},"codeBytes":{"type":"number"},"isContract":{"type":"boolean"},"minimalProxy":{"type":"boolean"},"implementation":{}}}}}}},"responseSchema":{"type":"json","example":{"chain":"Base","address":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","chainId":8453,"codeBytes":1855,"isContract":true,"minimalProxy":false,"implementation":null}},"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.003","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":"$0.003/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.003","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.003","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_QAwU_b0HPuVyz6XccByJ-","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.003","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Checks whether a given 0x address on the Base blockchain is a smart contract or an externally-owned account (EOA), and returns contract metadata including code size, minimal proxy detection, and implementation address.","exampleAgentPrompt":"Can you check if 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 is a smart contract or a regular wallet on Base, and tell me if it's a proxy?","exampleUseCases":[{"title":"Token contract verification before DeFi interaction","prompt":"Before I interact with it, can you check if 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 is actually a smart contract on Base and not just a wallet address?"},{"title":"Minimal proxy detection for security audit","prompt":"I'm auditing a Base address — can you tell me if 0x4200000000000000000000000000000000000006 is a minimal proxy contract and what its implementation address is?"},{"title":"EOA vs contract classification for airdrop filtering","prompt":"I need to filter out non-contract addresses from my list — can you check if 0xd9aAEc86B65D86f6A7B5B1b0c42FFA531710b6CA on Base is a smart contract and how many bytes of code it has?"}],"resultDescription":"Returns a JSON object with: chain name ('Base'), chainId (8453), the queried address, codeBytes (number of bytecode bytes at the address), isContract (true/false boolean), minimalProxy (true/false indicating EIP-1167 minimal proxy pattern), and implementation (the logic contract address if it's a proxy, or null).","failureModes":["Invalid or malformed 0x address returns an error","Address not found on Base (e.g. address never deployed) returns isContract: false","Network/RPC errors on Base may cause transient failures (not charged on failure)","Non-checksummed addresses may cause validation errors"],"whenToPreferThis":"Use this endpoint when you specifically need to classify a Base-chain address as contract vs EOA, detect minimal proxy patterns, or retrieve code size — especially in DeFi, security, or compliance workflows where knowing whether an address holds executable code matters. Prefer this over generic Ethereum tools when the target chain is Base (chainId 8453).","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-19T12:41:23.873Z","isFirstParty":false,"canonicalSlug":"base-is-contract-checker-2e59f779"}