{"uid":"cap_pb5_RAieDXe93QCWKGfIL","slug":"propeller-rocks-function-selector-event-topic0-computer-29c14d5e","name":"propeller.rocks Function Selector / Event Topic0 Computer","description":"Compute the 4-byte function selector or event topic0 from a signature","url":"https://propeller.rocks/selector","method":"GET","headers":{},"bodySchema":null,"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_tWS2zcbQRR4lbDJRE4WUy","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.001","costPer":"request","priority":0,"asset":null,"unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Computes the 4-byte function selector or 32-byte event topic0 hash from an ABI function or event signature","exampleAgentPrompt":"What's the 4-byte function selector for the Solidity signature transfer(address,uint256)?","exampleUseCases":null,"resultDescription":"Returns the 4-byte function selector (for function signatures) or 32-byte topic0 hash (for event signatures) derived from the keccak256 hash of the input signature string, as a hex-encoded value.","failureModes":["Invalid or malformed signature string returns an error","Missing signature input returns a validation error","Network or payment failure results in no response","Ambiguous signature format may produce unexpected results"],"whenToPreferThis":"Use this endpoint when you need to derive the canonical 4-byte selector or event topic0 from a human-readable Solidity function or event signature, without running a full ABI encoder or local keccak256 library. Ideal for EVM tooling workflows where you need to identify or filter transactions and logs by selector.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-15T12:33:14.360Z","isFirstParty":false}