{"uid":"cap_UP54_LoArQVpulM6_l5uv","slug":"preflight-evm-transaction-inspector-0d948800","name":"Preflight EVM Transaction Inspector","description":"Call before signing an Ethereum or Base transaction or calldata. Decodes raw transaction bytes or contract calldata against standard interfaces (ERC-20, ERC-721, ERC-1155, WETH, EIP-2612 Permit and Permit2) in memory. Returns the decoded method signature, typed parameters, value in wei and standard specification links. Mechanical byte decoding only: never simulates state or advises whether to sign.","url":"https://preflight402.com/v1/evm/tx-inspect?utm_source=zero.xyz","method":"POST","headers":{},"bodySchema":{"type":"object","properties":{"to":{"type":"string","pattern":"^0x[0-9a-fA-F]{40}$"},"raw_tx":{"type":"string","pattern":"^0x([0-9a-fA-F]{2})*$"},"network":{"enum":["ethereum","base"],"type":"string"},"calldata":{"type":"string","pattern":"^0x([0-9a-fA-F]{2})*$"}}},"responseSchema":null,"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.1","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":"$0.1/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_edjlXbz3JHaza-REk4K5f","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.1","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Decodes raw Ethereum or Base transaction bytes or calldata against standard interfaces (ERC-20, ERC-721, ERC-1155, WETH, EIP-2612 Permit, Permit2) and returns the decoded method signature, typed parameters, value in wei, and spec links.","exampleAgentPrompt":"Before I sign this Ethereum transaction, decode the raw calldata for me — it starts with 0xa9059cbb... — and tell me what method is being called, the recipient address, and the token amount in wei.","exampleUseCases":[{"title":"Decode ERC-20 transfer before signing","prompt":"I'm about to sign this raw Ethereum calldata — 0xa9059cbb000000000000000000000000ab5801a7d398351b8be11c439e05c5b3259aec9000000000000000000000000000000000000000000000000002386f26fc10000 — can you decode it and tell me the method name, recipient address, and amount?"},{"title":"Inspect Permit2 approval on Base","prompt":"I got a Permit2 signature request on Base with this calldata: 0x2b67b570... — decode it for me before I sign, I want to see the typed parameters and what token and spender it's approving."},{"title":"Parse WETH deposit transaction","prompt":"What does this raw transaction hex actually do on Ethereum? Here it is: 0xd0e30db0... — I think it's a WETH deposit but I want to see the decoded method signature and value in wei to confirm before I broadcast it."}],"resultDescription":"Returns the decoded method name/signature, typed input parameters with their values, the ETH value in wei attached to the transaction, the matched standard interface (e.g. ERC-20, ERC-721, Permit2), and links to the relevant EIP/standard specification. No state simulation or signing advice is included.","failureModes":["Calldata does not match any supported interface (ERC-20, ERC-721, ERC-1155, WETH, Permit, Permit2) — returns unrecognized or raw fallback","Malformed hex input (odd-length or non-hex characters) — returns validation error","Missing both raw_tx and calldata — returns parameter error","Unsupported network specified — returns enum validation error","Payment not received (x402 payment required) — returns 402 Payment Required"],"whenToPreferThis":"Use this endpoint when an agent or user needs to understand what a raw Ethereum or Base transaction or calldata is doing before signing it, without executing or simulating it. Ideal for pre-signing safety checks on standard token interactions (ERC-20 transfers, NFT transfers, WETH wraps, permit approvals). Prefer this over full simulation tools when only byte-level decoding is needed and no on-chain state lookup is required.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-02T00:43:55.537Z","isFirstParty":false,"canonicalSlug":"preflight-evm-transaction-inspector-0d948800"}