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Portals Foresight — DeFi Transaction Simulation API
x402
Portals Foresight — DeFi Transaction Simulation API is a paid API for AI agents from foresight.portals.fi, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-12).
Simulate any EVM transaction on 31+ chains to preview asset changes, gas costs, and DeFi outcomes without executing on-chain
Price / call$0.001
Success—
StatusUnknown
How this service works
Simulate any EVM transaction on 31+ chains. Compare DEX quotes, validate DeFi deposits/borrows, preview swaps, and verify transfers — no gas or balance needed.
Output
Returns a JSON object with: success flag, gas used and gas cost in wei, decoded events (e.g. wrap/swap), inputTokens and outputTokens with addresses/amounts/standards, assetChanges with direction (sent/received) for each token, sender address, and tokenMetadata (name, symbol, decimals) for all involved tokens.
Example use cases
Example prompt
“Before I actually submit this transaction, can you simulate it for me — I'm sending 1 ETH (1000000000000000000 wei) from 0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045 to 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2 with calldata 0xd0e30db0, input token is native ETH (0x0000000000000000000000000000000000000000), and I want to see exactly what asset changes and gas costs I'd get without actually executing on-chain.”
Technical details
Endpoint
POSThttps://foresight.portals.fi/v1/simulate?utm_source=zero.xyzWhen to prefer
Use this endpoint when you need to dry-run any EVM transaction — especially DeFi operations like swaps, deposits, borrows, or wraps — and want to preview exact asset changes, output token amounts, and gas costs before committing on-chain. Prefer it over DEX quote APIs when you need verified simulation results across 31+ chains including full event decoding, or when you need to validate that a transaction will succeed without holding a balance or paying gas.
Side effects
- Transaction reverts on simulation — success:false returned with revert reason
- Invalid or non-checksummed contract address — 400 bad request
- Unsupported chain — endpoint returns error for chains outside the 31+ supported
- Malformed calldata hex string — 400 validation error
- inputAmount as non-decimal string (e.g. hex) — parsing error
- Payment not included or insufficient — 402 payment required
- Rate limiting or Pro plan required for customEvents without x402 — 402/403 error
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
Schema · Response
{
"type": "json",
"example": {
"events": [
{
"type": "wrap",
"token": "0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2",
"amount": "1000000000000000000"
}
],
"sender": "0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045",
"gasCost": "838140000000000",
"gasUsed": "27938",
"success": true,
"inputTokens": [
{
"token": "0x0000000000000000000000000000000000000000",
"amount": "1000000000000000000",
"standard": "native"
}
],
"assetChanges": [
{
"token": "0x0000000000000000000000000000000000000000",
"amount": "1000000000000000000",
"standard": "native",
"direction": "sent"
},
{
"token": "0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2",
"amount": "1000000000000000000",
"standard": "erc20",
"direction": "received"
}
],
"outputTokens": [
{
"token": "0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2",
"amount": "1000000000000000000",
"standard": "erc20"
}
],
"tokenMetadata": {
"0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2": {
"name": "Wrapped Ether",
"symbol": "WETH",
"decimals": 18
}
}
}
}Tags
x402
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