{"uid":"cap_rlHpWakd6rtuFuyLBGsxk","slug":"transaction-simulation-dry-run-before-signing-b3edeadb","name":"Transaction Simulation (Dry-Run Before Signing)","description":"Transaction simulation: will this tx succeed or revert, and why? Returns success/revert reason, return data, and decoded action. Send { chain, to, data, from?, value? }. Dry-run before signing.","url":"https://x402-services-production.up.railway.app/api/safety/simulate","method":"POST","headers":{},"bodySchema":{"type":"object","required":["to"],"properties":{"to":{"type":"string","description":"0x target address"},"data":{"type":"string","description":"0x calldata"},"from":{"type":"string","description":"0x sender"},"chain":{"type":"string","description":"Chain, default base"},"value":{"type":"string","description":"Native value in wei"}}},"responseSchema":null,"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.05","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":"$0.05/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.05","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.05","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_4CB-53dLVtw-z4vEL4ilT","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.05","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Simulates an EVM transaction to predict whether it will succeed or revert, returning the revert reason, return data, and decoded action — without spending gas.","exampleAgentPrompt":"Before I sign this transaction, can you simulate it on Base to check if it'll succeed or revert? The target is 0xAbCd...1234, the calldata is 0xa9059cbb...0064, sent from 0xMySelf...5678 with 0 value.","exampleUseCases":null,"resultDescription":"Returns whether the transaction would succeed or revert, the revert reason string if it would fail, raw return data, and a decoded human-readable description of the action being performed.","failureModes":["Invalid or malformed 'to' address returns a 400 error","Unsupported chain identifier causes a lookup failure","Malformed calldata may result in an undecodeable action with partial results","Simulation against stale state may not reflect real-time chain conditions","Missing required 'to' field returns a validation error"],"whenToPreferThis":"Use this endpoint when an AI agent or user wants to pre-flight an EVM transaction before signing or broadcasting it — especially when the calldata is complex, the user is unsure whether a contract call will succeed, or you need to decode what a transaction actually does. Prefer this over just broadcasting when gas safety or user confirmation is important.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-14T18:45:09.196Z","isFirstParty":false}