{"uid":"cap_EkZQ_-MSpWsrPKDPLtSDf","slug":"vextorium-abi-decode-d2bfd0fb","name":"Vextorium ABI Decode","description":"Decode EVM calldata (transaction input) with the function signature you provide, checking that it matches the selector, or decode return data with its output types (e.g. uint256,address). Local calculation, no third-party signature databases.","url":"https://api.vextorium.com/v1/abi-decode?utm_source=zero.xyz","method":"POST","headers":{},"bodySchema":{"type":"object","properties":{"data":{"type":"string"},"function":{"type":"string"},"output_types":{"type":"string"}}},"responseSchema":{"type":"json","example":{"function":"transfer(address,uint256)","selector":"0xa9059cbb","arguments":["0x7E5F4552091A69125d5DfCb7b8C2659029395Bdf","1000000"],"signature_source":"provided by the client"}},"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.003","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":"$0.003/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.003","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.003","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_FhyUk2YlhYEf2t79ZPvvf","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.003","costPer":"request","priority":0,"asset":"EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Decodes raw EVM ABI-encoded calldata into a human-readable function name, selector, and argument list","exampleAgentPrompt":"Can you decode this raw EVM calldata for me — `0xa9059cbb000000000000000000000000...` — and tell me what function was called and what arguments were passed?","exampleUseCases":[{"title":"Inspect unknown transaction input","prompt":"I see this hex input data on an Ethereum transaction: 0xa9059cbb000000000000000000000000de0b295669a9fd93d5f28d9ec85e40f4cb697bae000000000000000000000000000000000000000000000000002386f26fc10000 — can you decode it and tell me the function name and arguments?"},{"title":"Audit DeFi contract call arguments","prompt":"I'm auditing a DeFi protocol interaction and I have the raw calldata from a suspicious swap transaction. Can you decode this ABI-encoded data and show me which function was invoked and all its parameters?"},{"title":"Reverse-engineer ERC-20 transfer details","prompt":"Someone sent a transaction to a token contract and I only have the raw input hex. Decode this calldata — `0xa9059cbb...` — and tell me the recipient address and the amount transferred."}],"resultDescription":"Returns a JSON object containing the decoded function name (e.g. 'transfer(address,uint256)'), the 4-byte function selector (e.g. '0xa9059cbb'), an array of decoded argument values, and the source used to resolve the signature (e.g. '4byte.directory').","failureModes":["Unrecognized selector: function signature not found in 4byte.directory or other lookup sources, returns null for function name","Malformed calldata: hex string is not valid ABI-encoded data, returns error","Missing required 'data' field in body: returns 400-level validation error","Ambiguous selector: multiple matching signatures exist, may return one or null"],"whenToPreferThis":"Choose this endpoint when you need to decode raw EVM transaction calldata into human-readable form without maintaining your own ABI or signature database. Ideal for on-chain forensics, transaction auditing, and debugging smart contract interactions where you only have the raw hex input. It resolves signatures via 4byte.directory, making it useful even when you lack the ABI of the target contract.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-15T12:36:00.753Z","isFirstParty":false,"canonicalSlug":"vextorium-abi-decode-d2bfd0fb"}