{"uid":"cap_VVLN1CJZjBTwFH6LzYzZ-","slug":"multichain-rpc-proxy-implementation-lookup-fdf0431a","name":"Multichain RPC Proxy Implementation Lookup","description":"Cheap, factual EVM chain lookups priced per call in USDC. Base, Polygon, Arbitrum, Optimism and Ethereum.","url":"https://multichain-rpc.clankerceo.workers.dev/proxy-implementation","method":"GET","headers":{},"bodySchema":{"type":"object","$schema":"https://json-schema.org/draft/2020-12/schema","required":["input"],"properties":{"input":{"type":"object","required":["type","method","queryParams"],"properties":{"type":{"enum":["http"],"type":"string"},"method":{"enum":["GET"],"type":"string"},"queryParams":{"type":"object","properties":{"chain":{"type":"string"},"address":{"type":"string"}}}}},"output":{"type":"object","required":["type"],"properties":{"type":{"enum":["json"],"type":"string"},"example":{"type":"object"}}}}},"responseSchema":{"type":"json","example":{"chain":"base","address":"0x…","pattern":"eip1967.implementation","is_proxy":true,"implementation":"0x…"}},"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_NaL2UDolO83_Iar12GBOu","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":"Detects whether a smart contract on EVM chains is a proxy and resolves the underlying implementation address using EIP-1967 and similar patterns.","exampleAgentPrompt":"Is the contract at 0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48 on Ethereum a proxy, and if so what's its implementation address?","exampleUseCases":[{"title":"Auditing an upgradeable DeFi protocol","prompt":"Check if the contract 0x7Fc66500c84A76Ad7e9c93437bFc5Ac33E2DDaE9 on Ethereum is a proxy contract and tell me what implementation address it points to."},{"title":"Verifying token contract on Base","prompt":"I need to know if the contract 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base is a proxy — can you look up whether it uses EIP-1967 and resolve the actual logic contract?"},{"title":"Cross-chain proxy resolution for security review","prompt":"For both the Polygon and Arbitrum deployments of contract 0x2791Bca1f2de4661ED88A30C99A7a9449Aa84174, check if they're proxy contracts and return the underlying implementation addresses."}],"resultDescription":"A JSON object containing: the queried chain name, the queried contract address, whether the contract is a proxy (is_proxy boolean), the detected proxy pattern (e.g. 'eip1967.implementation'), and the resolved implementation contract address if a proxy was detected.","failureModes":["Invalid or unrecognized chain name returns an error — use supported values: base, polygon, arbitrum, optimism, ethereum","Malformed or checksumless contract address returns a parsing error","Contract is not a proxy — returns is_proxy: false with no implementation address","RPC node unavailable for the target chain — may return a 5xx or timeout","Non-existent contract address (no bytecode) may return is_proxy: false or an error","Payment failure via x402 protocol blocks the request with a 402 response"],"whenToPreferThis":"Choose this endpoint when you need to determine if a smart contract is upgradeable and resolve its actual logic contract across Base, Polygon, Arbitrum, Optimism, or Ethereum. It is purpose-built for proxy detection using recognized patterns like EIP-1967 and is priced per-call at $0.002 USDC, making it cost-effective for spot lookups. Prefer it over general-purpose RPC calls when you want a structured, pre-parsed proxy resolution result rather than raw storage slot reads.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-14T18:03:58.566Z","isFirstParty":false}