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true402 Base Chain Transaction Preflight
x402
true402 Base Chain Transaction Preflight is a paid API for AI agents from true402.dev, paid per call via x402, $0.008/call, status unknown (last checked 2026-09-14).
Simulates a Base blockchain transaction to predict gas costs, revert reasons, and execution outcomes before submission.
Price / call$0.008
Success—
StatusUnknown
How this service works
The machine-native marketplace. Wallet = identity. Pay per call with HTTP 402.
Output
Returns a simulation result object indicating whether the transaction would succeed or revert, predicted gas usage, any revert reason or error message, and execution trace details for the given Base chain transaction parameters.
Example use cases
Pre-flight smart contract interaction
“I want to call the approve function on a Base ERC-20 token contract before actually submitting it — can you simulate the transaction from my wallet 0xABC... to contract 0xDEF... with calldata 0x095ea7b3... and 0 wei to see if it will revert?”
Gas estimation for native transfer
“Can you preflight a plain ETH transfer on Base from 0x111... to 0x222... for 500000000000000000 wei so I can see the expected gas cost before I broadcast it?”
DeFi swap safety check
“Before I execute this DEX swap on Base, run a simulation with sender 0xAAA..., destination router 0xBBB..., calldata 0x38ed1739..., and value 0 — I want to confirm it won't revert before committing real funds.”
Technical details
Endpoint
POSThttps://true402.dev/api/v1/base/tx-preflightWhen to prefer
Use this endpoint when you need to validate a Base blockchain transaction before broadcasting — especially for smart contract interactions where revert risk is high, or when estimating gas costs without spending funds. Prefer this over generic Ethereum mainnet simulators when targeting Base (Coinbase L2). Ideal for AI agents managing wallets that need confidence in transaction safety before committing.
Side effects
- Invalid or malformed Ethereum address in 'to' or 'from' fields — returns validation error
- Malformed calldata hex string — returns parse error
- Simulation reverts due to insufficient balance, bad calldata, or contract logic — revert reason returned in response
- Node or RPC unavailability causing simulation timeout
- 'from' address has no on-chain state, affecting simulation accuracy
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| torequired | string | Destination contract or address |
| data | string | Calldata hex (0x…); omit for a plain native transfer |
| fromrequired | string | Sender address. Asserted, never proven — no signature is taken. |
| value | string | Native value in wei as a decimal string; default 0 |
Output
Schema · Response
{
"type": "object"
}Tags
x402
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