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EVM Transaction Simulator
x402
EVM Transaction Simulator is a paid API for AI agents from defi.hugen.tokyo, paid per call via x402, $0.02/call, status unknown (last checked 2026-09-15).
Simulates an EVM transaction before execution to preview gas costs, token balance changes, approval modifications, and detect sandwich attacks or unexpected transfers on any EVM chain
Price / call$0.02
Success—
StatusUnknown
How this service works
Simulate an EVM transaction before execution — preview gas costs, token balance changes, approval modifications, and detect sandwich attacks or unexpected transfers. Supports any EVM chain. Premium endpoint ($0.02). No API keys needed. Accepts USDC payments on Base and Solana
Output
Returns a simulation result including estimated gas cost, token balance deltas for all affected addresses, any token approval modifications, detection of sandwich attack vectors, and flags for unexpected or anomalous transfers — all without broadcasting to the network.
Example use cases
Example prompt
“Before I sign this transaction, can you simulate it on Ethereum mainnet and show me the expected gas cost, any token balance changes, approval changes, and whether it's vulnerable to a sandwich attack? Here's the raw transaction data: 0x...”
Technical details
Endpoint
POSThttps://defi.hugen.tokyo/defi/simulateWhen to prefer
Use this endpoint when you need to pre-flight any EVM transaction before broadcasting — especially for DeFi interactions involving token swaps, approvals, or bridge calls where gas cost predictability, MEV/sandwich attack risk, and unexpected side effects matter. Prefer this over manual gas estimation tools when you need a full simulation of balance changes, approvals, and security checks in a single call across any EVM-compatible chain.
Side effects
- Invalid or malformed transaction data returns a parsing error
- Unsupported EVM chain ID returns an unsupported chain error
- Simulation reverts if the transaction would revert on-chain
- Insufficient USDC payment returns a 402 payment required response
- Network congestion or node unavailability may cause timeout errors
Input
{
"to": "0x68b3465833fb72B5A828cCEEad996fc3cA6B0A89",
"data": "0xa9059cbb0000000000000000000000001234567890123456789012345678901234567890000000000000000000000000000000000000000000000000016345785d8a0000",
"from": "0x1234567890123456789012345678901234567890",
"value": "0",
"chain_id": 1,
"gas_limit": "100000"
}Schema · Request body
| Field | Type | Description |
|---|---|---|
| input | — |
Output
{
"logs": [],
"flagged": [],
"used_gas": 0,
"is_revert": false,
"is_simulated": false,
"revert_reason": "",
"suspicious_url": false,
"suspicious_addresses": [],
"erc20_balance_changes": [],
"erc721_balance_changes": [],
"native_balance_changes": [],
"simulate_failed_reason": "",
"erc1155_balance_changes": [],
"erc20_allowance_changes": [],
"erc721_allowance_changes": [],
"erc1155_allowance_changes": []
}Tags
x402
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