{"uid":"cap_X1bKzxF72Nnl4OZfyIFFo","slug":"evm-transaction-simulator-eth-call-eth-estimategas-c542efb2","name":"EVM Transaction Simulator (eth_call + eth_estimateGas)","description":"Dry-run a prospective smart-contract call or transaction without broadcasting it: executes eth_call and eth_estimateGas against the latest block over the same keyless multi-endpoint public RPC pool as /api/evm-rpc (ethereum, base, polygon, arbitrum, optimism). Returns the return data and a gas estimate on success, or {success:false} with the revert reason when the call would fail. Strictly read-only - nothing is signed or broadcast.","url":"https://agent402.tools/api/tx-simulate","method":"POST","headers":{},"bodySchema":{"type":"object","properties":{"to":{"type":"string","description":"0x-prefixed 40-char target contract/account address."},"data":{"type":"string","description":"0x-prefixed calldata (default 0x - plain value transfer)."},"from":{"type":"string","description":"Optional sender address (default zero address)."},"value":{"type":"string","description":"Optional value in wei - decimal string or 0x hex (default 0)."},"network":{"type":"string","description":"ethereum / base / polygon / arbitrum / optimism (default base)."}}},"responseSchema":{"type":"json","example":{"network":"base","success":true,"returnData":"0x00000000000000000000000000000000000000000000000000000000000f4240","gasEstimate":31234,"revertReason":null}},"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.005","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":"$0.005/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.005","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.005","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_NXnr7sDnFBQr8rkQNB8uo","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.005","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Dry-runs a smart contract call or transaction on EVM-compatible networks using eth_call and eth_estimateGas without broadcasting to the blockchain.","exampleAgentPrompt":"Before I send this transaction, can you simulate calling contract 0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48 on Ethereum with calldata 0x70a08231000000000000000000000000d8dA6BF26964aF9D7eEd9e03E53415D37aA96045 from my address 0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045 and tell me the return value and estimated gas?","exampleUseCases":null,"resultDescription":"Returns the eth_call return data (decoded output bytes from the contract) and the eth_estimateGas value (integer gas units required), giving the agent visibility into whether the transaction would succeed, what it would return, and how much gas it would consume — all without submitting anything to the chain.","failureModes":["Contract reverts: simulation succeeds but returns a revert reason string or custom error bytes","Invalid address format: 400 error if 'to' is not a valid 0x-prefixed 40-char hex address","Unsupported network: error if network value is not one of ethereum/base/polygon/arbitrum/optimism","Invalid calldata: malformed 0x hex in 'data' field causes RPC-level error","RPC pool timeout: upstream public RPC node unresponsive, returns 5xx","Payment failure: x402 payment of $0.005 USDC not received, request rejected"],"whenToPreferThis":"Use this endpoint when you need to validate or preview a smart contract interaction on any major EVM chain before committing a real transaction. Ideal for agents that need to check for reverts, estimate gas budgets, or inspect return values without risking funds or paying on-chain gas. Prefer this over calling a chain's RPC directly when you want a managed multi-chain pool that already handles endpoint failover across ethereum, base, polygon, arbitrum, and optimism.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-15T01:05:55.045Z","isFirstParty":false}