{"uid":"cap_PIe2_5y4iPUc9VVHVUvXp","slug":"evm-calldata-decoder-aff7cb83","name":"EVM Calldata Decoder","description":"Exact EVM address, calldata, Uniswap V2/V3 and impermanent-loss math. Pay per call in USDC on Base via x402.","url":"https://golf-evm-math.x402-evm-math.workers.dev/evm/decode?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":{"type":"string","const":"http"},"method":{"enum":["GET"],"type":"string"},"queryParams":{"type":"object","properties":{}}},"additionalProperties":false},"output":{"type":"object","required":["type"],"properties":{"type":{"type":"string"},"example":{"type":"object"}}}}},"responseSchema":{"type":"json","example":{"known":true,"selector":"0xa9059cbb"}},"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_H4wsgUevUHIfvxiBIkPyt","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":"Decodes EVM calldata hex strings into human-readable function signatures and typed arguments using a built-in table of ~60 common ERC20/721/1155, Uniswap, and Aave signatures, or a user-supplied signature.","exampleAgentPrompt":"Can you decode this EVM calldata for me: 0xa9059cbb000000000000000000000000ab5801a7d398351b8be11c439e05c5b3259aec9000000000000000000000000000000000000000000000000016345785d8a0000 — I want to know what function was called and what the arguments are.","exampleUseCases":[{"title":"Decode ERC20 transfer calldata","prompt":"I have this transaction input data from an Ethereum transfer: 0xa9059cbb000000000000000000000000deadbeef...0000000000000000000000000000000000000000000000000de0b6b3a7640000 — can you decode it into a human-readable function call and show me the recipient and amount?"},{"title":"Identify Uniswap swap function","prompt":"I'm analyzing a Uniswap transaction and the input data starts with 0x38ed1739. Can you decode the full calldata and tell me which Uniswap function was called and what the swap parameters are?"},{"title":"Custom ABI calldata decoding","prompt":"I have some calldata from a contract: 0x12345678... and I know the signature is mint(address,uint256). Can you decode the arguments using that custom signature so I can see what was passed in?"}],"resultDescription":"Returns a JSON object indicating whether the function selector is known, the 4-byte selector (e.g. 0xa9059cbb), the resolved function signature name and parameter types, and the decoded typed argument values extracted from the calldata.","failureModes":["Unknown selector not in built-in table and no custom signature supplied — returns known:false with no decoded args","Malformed or non-hex calldata input — returns error response","Calldata too short to contain a valid 4-byte selector — parse error","Supplied custom signature does not match the calldata selector — decoding mismatch","Network or payment authorization failure returns 402 Payment Required"],"whenToPreferThis":"Choose this endpoint when you need to quickly decode EVM transaction calldata without setting up a full ABI decoder or node connection, especially for common DeFi protocols (ERC20, ERC721, ERC1155, Uniswap, Aave). Ideal for transaction analysis pipelines, on-chain monitoring, and debugging tools. Supports custom signatures for non-standard contracts.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-30T07:06:13.674Z","isFirstParty":false,"canonicalSlug":"evm-calldata-decoder-aff7cb83"}