{"uid":"cap_XM6h8F-ApaiBBsKbiXog_","slug":"contract-check-78146a95","name":"Contract Check","description":"Determine whether an address on Base is a contract or an externally owned account. POST {\"address\":\"0x...\"} and receive isContract, the bytecode size in bytes and its keccak-256 hash. Useful before sending funds to an unfamiliar address.","url":"https://x402-echo-service.onrender.com/chain/code","method":"POST","headers":{},"bodySchema":{"type":"object","properties":{"address":{"type":"string"}}},"responseSchema":null,"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_TDABE4LABfYNxt7mEp3Fm","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":"Determines whether a Base blockchain address is a smart contract or an externally owned account (EOA), returning bytecode size and keccak-256 hash.","exampleAgentPrompt":"Before I send funds, can you check if 0x1234567890abcdef1234567890abcdef12345678 on Base is a smart contract or just a regular wallet?","exampleUseCases":[{"title":"Pre-transfer address safety check","prompt":"I'm about to send 2 ETH to 0xAbCd1234567890abcdef1234567890abcdef5678 — can you tell me if it's a smart contract or a plain wallet on Base before I do?"},{"title":"DeFi integration contract validation","prompt":"Can you confirm that 0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48 on Base is actually a deployed smart contract and give me its bytecode size and code hash?"},{"title":"Suspicious address investigation","prompt":"Someone sent me a payment request from 0xdeadbeef1234567890abcdef1234567890abcd12 on Base — is that address a contract or a real wallet? I want to know its bytecode details before I interact with it."}],"resultDescription":"Returns a JSON object with: isContract (boolean indicating whether the address has deployed code), bytecodeSize (integer, size of the code in bytes — 0 for EOAs), and a keccak-256 hash of the bytecode for contract fingerprinting.","failureModes":["Invalid or malformed Ethereum address returns an error response","Address with no on-chain activity may return isContract: false with size 0","Network connectivity issues with the Base RPC may cause timeouts","Self-destructed contracts may return isContract: false even if formerly deployed"],"whenToPreferThis":"Use this endpoint when you need to quickly classify a Base address as a contract or EOA before sending funds, interacting programmatically, or auditing an address. Prefer this over a general block explorer lookup when you need machine-readable output (isContract boolean, bytecode size, code hash) for automated decision-making in an agent workflow.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-14T00:38:00.932Z","isFirstParty":false}