{"uid":"cap_vM3Efa25H3ZLiyaBCaiL8","slug":"x402-audit-calldata-decoder-22286802","name":"x402-audit Calldata Decoder","description":"Pay-per-call on-chain API for AI agents and developers: wallet audits, token safety audits (honeypot detection), live gas prices, token prices, transaction receipts, balances, ENS resolution, block data, ERC-20 allowances, transaction simulation, swap quotes and multicall batches — all computed on-chain via public RPCs (no external market API). Pay per request in USDC on Base via the x402 exact scheme (EIP-3009 transferWithAuthorization). No API key, no signup, no subscription.","url":"https://x402-audit.tatschluizguilherme.workers.dev/decode?utm_source=zero.xyz","method":"GET","headers":{},"bodySchema":null,"responseSchema":{"type":"json","example":{"data":"0xa9059cbb000000000000000000000000d8dA6BF26964aF9D7eEd9e03E53415D37aA9604500000000000000000000000000000000000000000000000000000000000f4240","network":"offline","function":{"args":["0xd8da6bf26964af9d7eed9e03e53415d37aa96045","1000000"],"name":"transfer","known":true,"nested":null,"selector":"0xa9059cbb","argsNamed":{"to":"0xd8da6bf26964af9d7eed9e03e53415d37aa96045","value":"1000000"},"signature":"transfer(address,uint256)","decodeError":false},"selector":"0xa9059cbb","inputSize":68,"requestedAt":"2026-08-05T08:00:00.000Z"}},"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.1","displayCostAsset":"USDC","priceDynamic":false,"priceHint":null,"priceStatus":"priced","priceSource":"registry","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":"$0.1/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.1","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.1","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_O5t9Ca0KZAHDG28Au1bgm","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.1","costPer":"request","priority":0,"asset":null,"unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Decodes raw Ethereum transaction calldata (hex) offline, returning the 4-byte selector, matched function name, typed named arguments, and nested sub-call decoding — no RPC or API key required.","exampleAgentPrompt":"Before I sign this transaction, can you decode the calldata '0xa9059cbb000000000000000000000000d8da6bf26964af9d7eed9e03e53415d37aa9604500000000000000000000000000000000000000000000000de0b6b3a7640000' and tell me exactly what function it calls and with what arguments?","exampleUseCases":[{"title":"Pre-sign DeFi transaction audit","prompt":"I'm about to sign a transaction with calldata '0x23b872dd000000000000000000000000abc...000000000000000000000000def...0000000000000000000000000000000000000000000000008ac7230489e80000' — can you decode it so I know if it's a transferFrom and who the recipient and amount are before I approve it?"},{"title":"Inspect multicall nested sub-calls","prompt":"Decode this multicall calldata for me: '0xac9650d8000000000000000000000000000000000000000000000000000000000000002000000000000000000000000000000000000000000000000000000000000000020000...' — I want to see every individual sub-call it contains and what each one does."},{"title":"Verify Gnosis Safe execTransaction","prompt":"I received an execTransaction calldata from a Gnosis Safe and I want to know what it's actually going to execute before I add my signature — here's the hex: '0x6a761202...'. Can you decode it and show me the inner call details?"}],"resultDescription":"Returns a JSON object containing the 4-byte function selector, the matched function name from the built-in dictionary (e.g. transfer, approve, swap, multicall), fully typed and named decoded arguments with their values, and where applicable, recursively decoded nested sub-calls (e.g. inner calls within multicall bytes[] arrays or Gnosis Safe execute payloads). Runs entirely offline with no blockchain RPC calls.","failureModes":["Unknown selector not in ~40-function dictionary returns selector only with no function match","Malformed or truncated hex calldata causes decoding error","Non-hex or empty input returns validation error","Deeply nested or non-standard ABI encodings may not fully decode inner payloads","Payment failure ($0.10 USDC x402) blocks request before decoding"],"whenToPreferThis":"Prefer this endpoint when you need instant, offline ABI decoding of raw calldata without requiring an RPC node, blockchain explorer, or API key. Ideal for pre-signing audits, relayer pipelines, or any agent that needs to understand what a transaction does before executing or approving it. Best for the ~40 common DeFi functions (ERC-20, Uniswap, Aave, Gnosis Safe, etc.); for exotic or custom contract ABIs not in the dictionary, a full ABI-aware decoder would be needed.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-03T00:42:41.026Z","isFirstParty":false,"canonicalSlug":"x402-audit-calldata-decoder-22286802"}