{"uid":"cap_lcF5JutroAvYCqGVq8il6","slug":"simulate-asset-changes-1e9b9936","name":"Simulate Asset Changes","description":"Pay-per-request access to CoinGecko, DefiLlama, Alchemy, and Etherscan APIs. No auth, no subscriptions.","url":"https://stablecrypto.dev/api/alchemy/simulation/simulate-asset-changes","method":"POST","headers":{},"bodySchema":{"type":"object","properties":{"to":{"type":"string","description":"Contract/recipient address"},"data":{"type":"string","description":"Transaction calldata"},"from":{"type":"string","description":"Sender address"},"value":{"type":"string","description":"ETH value in hex"},"network":{"type":"string","description":"Alchemy network slug, e.g. eth-mainnet, base-mainnet"}}},"responseSchema":null,"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.01","displayCostAsset":"USDC","priceDynamic":false,"priceHint":null,"priceStatus":"priced","priceSource":"settled","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":"$0.01/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.01","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.01","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_EP6LlejKq7ZID0MO1IgFW","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.01","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Simulates an Ethereum transaction and returns predicted asset changes before execution","exampleAgentPrompt":"Before I send this swap transaction, can you simulate what asset changes will happen on eth-mainnet? The sender is 0xAbC...123, the recipient contract is 0xDef...456, and the calldata is 0xa9059cbb... with a value of 0x0.","exampleUseCases":null,"resultDescription":"Returns a structured object describing predicted asset changes resulting from the simulated transaction, including token transfers, ETH balance deltas, and NFT movements, without broadcasting anything to the blockchain.","failureModes":["Invalid or malformed Ethereum address returns a 400 error","Unsupported network slug returns an error indicating the network is not recognized","Simulation failure due to on-chain revert returns an error with revert reason","Missing required fields (network, from, to) returns a validation error","Insufficient calldata for complex contract interactions may return incomplete results"],"whenToPreferThis":"Use this endpoint when you need to preview asset changes from a transaction before committing it on-chain, especially for DeFi swaps, token transfers, or smart contract interactions on Alchemy-supported networks like eth-mainnet or base-mainnet. Prefer this over generic RPC passthrough when you specifically need structured asset change output rather than raw simulation data.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-13T12:54:38.085Z","isFirstParty":false}