{"uid":"cap_jjpHeQ89XCgjF2hpr41Oa","slug":"ishob-transaction-simulator-24f6fafb","name":"ISHOB Transaction Simulator","description":"Simulate a transaction before signing it: what leaves and enters the wallet (native, ERC-20, NFTs, SPL) with USD values, approvals granted (unlimited / to non-contracts), revert reason, gas and fee, plus a risk level. EVM chains via eth_simulateV1 (raw call: from, to, data, value); Solana via simulateTransaction (base64 transaction, unsigned is fine). Nothing is broadcast.","url":"https://api.ishob.com/v1/crypto/simulate-tx?utm_source=zero.xyz","method":"POST","headers":{},"bodySchema":{"type":"object","properties":{"to":{"type":"string","description":"EVM: target address"},"gas":{"type":"string","description":"EVM: optional gas limit"},"data":{"type":"string","description":"EVM: calldata hex (default 0x)"},"from":{"type":"string","description":"EVM: sender address"},"chain":{"enum":["ethereum","base","arbitrum","optimism","polygon","bsc","solana"],"type":"string"},"value":{"type":"string","description":"EVM: value in wei (decimal or 0x hex)"},"transaction":{"type":"string","description":"Solana: base64-encoded transaction (legacy or v0; signatures not required)"}}},"responseSchema":{"type":"json","example":{"success":true,"gas_used":276293,"warnings":[],"approvals":[],"risk_level":"low","balance_changes":[{"usd":-24.9,"amount":"-0.01","symbol":"ETH","direction":"out"},{"usd":24.89,"amount":"24.894345","symbol":"USDC","direction":"in"}]}},"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.0015","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":"$0.0015/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.0015","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.0015","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_gG_MA9f2UMq807BLUsdu5","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.0015","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Dry-run an EVM or Solana transaction to see balance changes, approvals, revert reasons, gas cost, and risk level — without broadcasting it","exampleAgentPrompt":"Before I sign this swap, simulate it on Base — from 0xABC…123 to 0xDEF…456, calldata 0xa9059cbb…, value 0 — and tell me what tokens leave and enter my wallet, whether any unlimited approvals are granted, and what the risk level is.","exampleUseCases":[{"title":"DeFi swap safety check","prompt":"I'm about to do a Uniswap swap on Ethereum — can you simulate this transaction first and show me exactly how much ETH I'll spend, how much USDC I'll receive, and what the gas cost will be? From 0xMyWallet, to 0xUniswapRouter, calldata 0x…, value 10000000000000000 wei."},{"title":"Detect risky NFT approval","prompt":"Before I click confirm on this NFT marketplace approval, simulate the transaction on Polygon and flag if it grants unlimited token access to a non-contract address. From 0xMyAddress, to 0xMarketplaceContract, data 0x095ea7b3…."},{"title":"Solana program interaction preview","prompt":"I have a base64-encoded Solana transaction for a Jupiter swap — can you simulate it without broadcasting and tell me which SPL tokens will move in and out of my wallet, the estimated fee, and whether the risk level is high?"}],"resultDescription":"A JSON object with success status, list of balance changes (token symbol, amount, direction, USD value), list of approvals granted (flagging unlimited or non-contract recipients), revert reason if the transaction would fail, gas used, and an overall risk level (low/medium/high) with any warnings.","failureModes":["Unsupported chain returns validation error","Malformed calldata hex causes simulation failure","Transaction would revert — revert reason returned in response","Missing required fields (from/to for EVM, transaction for Solana) returns 400","Network congestion on the simulated chain may cause timeout","Invalid base64 Solana transaction returns parse error"],"whenToPreferThis":"Use this endpoint when an AI agent or user needs to preview the exact outcome of a blockchain transaction before committing — especially for DeFi interactions, NFT approvals, or unfamiliar contracts. It covers both EVM chains (Ethereum, Base, Arbitrum, Optimism, Polygon, BSC) and Solana in one call, returns USD-denominated values, and explicitly flags dangerous approval patterns and risk levels, making it superior to raw RPC simulation which provides no risk assessment or token USD values.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-14T06:44:54.732Z","isFirstParty":false,"canonicalSlug":"ishob-transaction-simulator-24f6fafb"}