{"uid":"cap_bs0Cply__D6Hz2yJxFufh","slug":"true402-base-chain-transaction-preflight-ee8c5df5","name":"true402 Base Chain Transaction Preflight","description":"The machine-native marketplace. Wallet = identity. Pay per call with HTTP 402.","url":"https://true402.dev/api/v1/base/tx-preflight","method":"POST","headers":{},"bodySchema":{"type":"object","required":["to","from"],"properties":{"to":{"type":"string","description":"Destination contract or address"},"data":{"type":"string","description":"Calldata hex (0x…); omit for a plain native transfer"},"from":{"type":"string","description":"Sender address. Asserted, never proven — no signature is taken."},"value":{"type":"string","description":"Native value in wei as a decimal string; default 0"}}},"responseSchema":{"type":"object"},"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.008","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":"$0.008/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.008","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.008","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_tlY4WHat4vJzJp2UWGlyX","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.008","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Simulates a Base blockchain transaction to predict gas costs, revert reasons, and execution outcomes before submission.","exampleAgentPrompt":"Before I send this contract call, simulate it on Base: from address 0xAbC123... to contract 0xDeF456..., with calldata 0xa9059cbb000000... and 0 wei value — will it succeed or revert?","exampleUseCases":[{"title":"Pre-flight smart contract interaction","prompt":"I want to call the approve function on a Base ERC-20 token contract before actually submitting it — can you simulate the transaction from my wallet 0xABC... to contract 0xDEF... with calldata 0x095ea7b3... and 0 wei to see if it will revert?"},{"title":"Gas estimation for native transfer","prompt":"Can you preflight a plain ETH transfer on Base from 0x111... to 0x222... for 500000000000000000 wei so I can see the expected gas cost before I broadcast it?"},{"title":"DeFi swap safety check","prompt":"Before I execute this DEX swap on Base, run a simulation with sender 0xAAA..., destination router 0xBBB..., calldata 0x38ed1739..., and value 0 — I want to confirm it won't revert before committing real funds."}],"resultDescription":"Returns a simulation result object indicating whether the transaction would succeed or revert, predicted gas usage, any revert reason or error message, and execution trace details for the given Base chain transaction parameters.","failureModes":["Invalid or malformed Ethereum address in 'to' or 'from' fields — returns validation error","Malformed calldata hex string — returns parse error","Simulation reverts due to insufficient balance, bad calldata, or contract logic — revert reason returned in response","Node or RPC unavailability causing simulation timeout","'from' address has no on-chain state, affecting simulation accuracy"],"whenToPreferThis":"Use this endpoint when you need to validate a Base blockchain transaction before broadcasting — especially for smart contract interactions where revert risk is high, or when estimating gas costs without spending funds. Prefer this over generic Ethereum mainnet simulators when targeting Base (Coinbase L2). Ideal for AI agents managing wallets that need confidence in transaction safety before committing.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-14T06:31:27.641Z","isFirstParty":false}