{"uid":"cap_HWubCcjfkA6kc8Lf0In7o","slug":"evm-function-selector-event-topic-decoder-57bc06e1","name":"EVM Function Selector & Event Topic Decoder","description":"Decode 4-byte function selectors and 32-byte event topics to text signatures (openchain). 0.01 USDC/call on Base.","url":"https://task-radar-x402.vercel.app/api/signature?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":{"const":"http"},"method":{"const":"GET"},"queryParams":{"type":"object","properties":{"selector":{"type":"string","description":"Comma-separated 0x 4-byte function selectors and/or 0x 32-byte event topics (max 20)"}}}}}}},"responseSchema":null,"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.01","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":"$0.01/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.01","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.01","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_NerodKjQ3TcJ7UCr6quIY","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.01","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Decodes 4-byte function selectors and 32-byte event topics into human-readable text signatures using the Openchain database","exampleAgentPrompt":"What function does the selector 0xa9059cbb map to, and can you also decode the event topic 0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef?","exampleUseCases":[{"title":"Identify unknown calldata in a transaction","prompt":"I see a transaction calling selector 0x23b872dd on a contract — can you decode that selector and tell me what function was called?"},{"title":"Decode event logs from a smart contract","prompt":"I've got this event topic 0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef from a contract log — what event does it correspond to?"},{"title":"Batch decode multiple selectors at once","prompt":"Can you decode all these function selectors for me at once: 0xa9059cbb, 0x23b872dd, 0x095ea7b3 — I need their human-readable function names."}],"resultDescription":"Returns the human-readable text signature(s) corresponding to the provided 4-byte function selector(s) or 32-byte event topic(s), such as 'transfer(address,uint256)' or 'Transfer(address,address,uint256)', sourced from the Openchain signature database. Up to 20 selectors/topics can be resolved per call.","failureModes":["Unknown selector or topic not found in Openchain database — returns empty or null result for that entry","Invalid hex format for selector or topic — returns error","Exceeding 20 selectors per call — returns validation error","Payment failure on Base network — 402 response requiring USDC payment"],"whenToPreferThis":"Use this endpoint when you need to reverse-lookup EVM function selectors or event topic hashes into human-readable ABI signatures, especially during transaction analysis, calldata decoding, or smart contract auditing. It supports batch lookup of up to 20 selectors/topics per call, making it efficient for bulk decoding. Prefer this over a full transaction decoder when you only have raw selectors and don't need full transaction context.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-31T18:40:23.954Z","isFirstParty":false,"canonicalSlug":"evm-function-selector-event-topic-decoder-57bc06e1"}