{"uid":"cap_HgI2Ay7Np_sGXrQIfXMVH","slug":"x402-bazaar-evm-function-selector-decoder-dea9ff2b","name":"x402 Bazaar — EVM Function Selector Decoder","description":"Resolves a 4-byte function selector (e.g. 0x70a08231) to candidate human-readable signatures via 4byte.directory. Accepts a bare selector or full calldata. Paid via x402: $0.005 in USDC on Base (eip155:8453) to 0x973a31858f4d2125f48c880542da11a2796f12d6. Returns 402 with payment requirements; pay and retry.","url":"https://api.relai.fi/relay/1782567677091/api/x402/decode-selector","method":"POST","headers":{},"bodySchema":{"type":"object","$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"},"pathParams":{"type":"object"},"queryParams":{"type":"object","required":["selector"],"properties":{"selector":{"type":"string","description":"Function selector"}}}},"additionalProperties":false}}},"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_j-g014ANC5ZbcTgQZXEs6","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":"Resolves a 4-byte Ethereum function selector or calldata to human-readable ABI signatures via 4byte.directory, paid with micro-USDC via x402 protocol","exampleAgentPrompt":"Can you decode the Ethereum function selector 0xa9059cbb and tell me what human-readable Solidity function signature it maps to?","exampleUseCases":null,"resultDescription":"Returns one or more candidate human-readable function signatures (e.g. 'transfer(address,uint256)') that match the provided 4-byte selector, sourced from the 4byte.directory database.","failureModes":["Unknown selector not present in 4byte.directory returns empty results","Malformed or non-hex selector returns a 400-style validation error","Payment not included or insufficient triggers 402 response with USDC payment requirements on Base","Selector provided with invalid length (not 4 bytes) rejected","Network issues reaching 4byte.directory upstream cause 502/timeout"],"whenToPreferThis":"Use this endpoint when you need to decode an unknown EVM function selector (4-byte hex) back to a human-readable Solidity signature — especially useful when analyzing smart contract calldata, debugging transactions, or building EVM tooling. Prefer this over querying 4byte.directory directly when you want a pay-per-call micropayment model via x402 without API key management.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-14T12:44:56.288Z","isFirstParty":false}