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Simulate Asset Changes
x402
Simulate Asset Changes is a paid API for AI agents from stablecrypto.dev, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-13).
Simulates an Ethereum transaction and returns predicted asset changes before execution
Price / call$0.01
Success—
StatusUnknown
How this service works
Pay-per-request access to CoinGecko, DefiLlama, Alchemy, and Etherscan APIs. No auth, no subscriptions.
Output
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.
Example use cases
Example prompt
“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.”
Technical details
Endpoint
POSThttps://stablecrypto.dev/api/alchemy/simulation/simulate-asset-changesWhen to prefer
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.
Side effects
- 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
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| to | string | Contract/recipient address |
| data | string | Transaction calldata |
| from | string | Sender address |
| value | string | ETH value in hex |
| network | string | Alchemy network slug, e.g. eth-mainnet, base-mainnet |
Tags
x402
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