{"uid":"cap_d_DOdynjkcL6AS5t0cMtb","slug":"jarvis-transaction-execution-preflight-api-9061e88b","name":"Jarvis Transaction Execution Preflight API","description":"One paid result for Base execution readiness: balances, nonce, target type, eth_call/gas simulation, reasons, evidence and hashes.","url":"https://jarvis-orderflow-router.yl124915300.workers.dev/v1/outcomes/tx-execution-preflight","method":"POST","headers":{},"bodySchema":{"type":"object","properties":{"to":{"type":"string","pattern":"^0x[0-9a-fA-F]{40}$"},"from":{"type":"string","pattern":"^0x[0-9a-fA-F]{40}$"},"chain":{"type":["string","integer"],"description":"Base mainnet: base, base-mainnet, eip155:8453, or 8453"},"value":{"type":"string","default":"0","pattern":"^(0|[1-9][0-9]*|0x[0-9a-fA-F]+)$","description":"Native value in wei"},"calldata":{"type":"string","default":"0x","pattern":"^0x(?:[0-9a-fA-F]{2})*$"}}},"responseSchema":{"type":"json","example":{"ok":true,"result":{"decision":"PAY","verification":{"result_hash":"sha256"}}}},"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_yZOPwt6UEh7AJzJj1oVLX","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":"Pre-flight checks a Base mainnet transaction by simulating execution readiness — verifying balances, nonce, target type, gas, and eth_call — before committing to on-chain submission.","exampleAgentPrompt":"Before I submit this transaction on Base mainnet, can you run a preflight check — from 0xAbC123...sender to 0xDeF456...contract, value 0 wei, calldata 0xa9059cbb...— and tell me if my balance and nonce are good, whether it'll revert, and what gas it needs?","exampleUseCases":[{"title":"DeFi swap safety check","prompt":"Before I execute this token swap on Base, can you preflight the transaction from my wallet 0xSenderAddress to the Uniswap router 0xRouterAddress with calldata 0xSwapCalldata and value 0 wei, and tell me if it'll succeed, what gas it needs, and whether my balance covers it?"},{"title":"NFT mint execution readiness","prompt":"I'm about to mint an NFT on Base mainnet — sender is 0xMyWallet, contract is 0xNFTContract, value is 5000000000000000 wei (the mint price), calldata is 0xMintCalldata — can you simulate this and confirm it won't revert before I send it?"},{"title":"Smart contract deployment preflight","prompt":"Can you run an execution preflight on Base for a contract deployment — from 0xDeployerAddress to 0x0000000000000000000000000000000000000000, no value, with this bytecode as calldata 0x608060...— and tell me the decision, gas estimate, and any reasons it might fail?"}],"resultDescription":"Returns a JSON object with an 'ok' boolean, a top-level 'result' containing a 'decision' field (e.g. 'PAY' or rejection reason), plus detailed verification sub-fields: balance adequacy, current nonce, target address type (EOA vs contract), eth_call simulation output, gas estimate, human-readable failure reasons, supporting evidence, and a SHA-256 result_hash for tamper-evidence.","failureModes":["Invalid Ethereum address format for 'to' or 'from' — returns 400 with validation error","Unsupported chain identifier — only Base mainnet (8453) is supported","Malformed calldata (odd-length hex, non-hex characters) — returns schema validation error","Simulation reverts — captured in result with revert reason and evidence rather than HTTP error","Insufficient balance detected — reflected in decision and reasons fields, not an HTTP error","Network/RPC unavailability — returns 5xx with connectivity error","Payment not included or failed x402 protocol — returns 402 Payment Required"],"whenToPreferThis":"Choose this endpoint when you need a comprehensive, single-call preflight check for a Base mainnet transaction that combines balance verification, nonce checking, target-type detection, eth_call simulation, and gas estimation in one paid result. Prefer it over rolling your own eth_call or balance check when you want structured decision output with hashed evidence for auditability, or when operating in an x402 payment-enabled agent pipeline on Base.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-14T00:31:02.208Z","isFirstParty":false}