{"uid":"cap_mcPuyMlDtHTCPUVqxQBV_","slug":"vextorium-evm-transaction-builder-8e8ca328","name":"Vextorium EVM Transaction Builder","description":"Build an EVM transaction ready to sign (never signed or sent): native transfer, ERC-20 transfer or ERC-20 approve, with to, data, value, nonce, chainId, estimated gas and current EIP-1559 fees, plus a simulation that warns if it would revert and the estimated cost.","url":"https://api.vextorium.com/construir-transaccion-pago?utm_source=zero.xyz","method":"POST","headers":{},"bodySchema":{"type":"object","properties":{"red":{"type":"string"},"para":{"type":"string"},"desde":{"type":"string"},"token":{"type":"string"},"accion":{"enum":["transferencia_nativa","transferencia_token","aprobar_token"],"type":"string"},"cantidad":{"type":"number"}}},"responseSchema":null,"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.004","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":"$0.004/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.004","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.004","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_Z_9U7FA2cIb3YJJSfxpct","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.004","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Builds an unsigned EVM transaction payload (native transfer, ERC-20 transfer, or ERC-20 approve) with full EIP-1559 fee estimates, gas, nonce, and chain ID — ready to sign.","exampleAgentPrompt":"Build me an unsigned EVM transaction to transfer 50 USDC from 0xABC...123 to 0xDEF...456 on Base — include the current EIP-1559 fees and gas estimate so I can sign and send it myself.","exampleUseCases":[{"title":"Prepare native ETH transfer on Arbitrum","prompt":"Build me a raw unsigned transaction to send 0.1 ETH from 0x1111...AAAA to 0x2222...BBBB on Arbitrum — I need the nonce, gas, and current EIP-1559 fees so I can sign it on my side."},{"title":"ERC-20 token approval for DeFi protocol","prompt":"I need to approve the Uniswap router at 0xRouter...XYZ to spend 1000 USDC from my wallet 0xMyWallet...123 on Ethereum mainnet — can you build the unsigned approve transaction with current gas fees?"},{"title":"Automated payment pipeline transaction prep","prompt":"Prepare an unsigned ERC-20 transfer transaction to move 200 DAI from 0xSender...AAA to 0xReceiver...BBB on Polygon — I need the full transaction object including calldata, nonce, chainId, and estimated cost in USD so my signing service can process it."}],"resultDescription":"Returns a fully formed unsigned transaction object containing: to, from, data (calldata), value (in hex), nonce, chainId, type, maxFeePerGas, maxPriorityFeePerGas, and gas (all hex-encoded), along with estimated gas units, estimated cost in USD, estimated cost in native token, token info (address, decimals), action type, network identifier, and an optional simulation note.","failureModes":["Invalid or missing wallet address (desde/para) returns validation error","Unsupported network identifier returns error indicating chain not found","Zero or negative amount fails input validation","Token address missing for transferencia_token or aprobar_token actions","RPC timeout on target chain causes gas estimation failure","Token contract not found on specified network"],"whenToPreferThis":"Choose this endpoint when you need to construct an EVM transaction for signing externally — ideal for wallets, signing services, or agents that manage their own private keys and need accurate EIP-1559 fee data baked in. Prefer this over on-chain submission services when you want to inspect, modify, or batch-sign transactions before broadcasting. Best suited for native transfers and ERC-20 transfers/approvals on supported EVM chains without needing to implement RPC calls yourself.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-29T07:27:04.709Z","isFirstParty":false,"canonicalSlug":"vextorium-evm-transaction-builder-8e8ca328"}