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OBOL EVM Transaction Preflight Simulator
x402
OBOL EVM Transaction Preflight Simulator is a paid API for AI agents from obol-x402.fly.dev, paid per call via x402, $0.1/call, status down (last checked 2026-09-15).
Simulates an EVM transaction before execution to predict success, revert reason, and gas estimate as a pre-trade safety verdict
Price / call$0.1
Success—
StatusDown
How this service works
Pre-trade safety for AI agents on Base, Ethereum, Arbitrum, Optimism, Polygon, BNB and Robinhood Chain. Is this token a rug — and can I sell it again? Signed verdicts before you buy, approve, send or sign: token rug/honeypot check with buy-sell tax, honeypot sell-simulation, pre-sign calldata guard (unlimited-approve / setApprovalForAll / drain-in-multicall), wallet risk with sanctions screening, tx preflight, and a launch feed with safety overlays. Plus unique Bitcoin forensics no RPC gives you: money-graph role, whale and exchange fingerprinting, Satoshi-era provenance, validation-gated block anomalies, and broadcast-fee timing. Every response Ed25519-signed and independently verifiable. Pay-per-call USDC on Base — no keys, no accounts, no signup. Free: /catalog, /llms.txt, and a preview for every paid SKU.
Output
Returns a JSON object with a 'verdict' field ('will_succeed' or similar), a 'revert' field (null if transaction will succeed, or a revert reason string), and a 'gas_estimate' integer representing predicted gas units. All responses are Ed25519-signed for independent verifiability.
Example use cases
Pre-swap revert check on Base
“I'm about to swap 500 USDC for ETH on Base — can you simulate the transaction first to make sure it won't revert? The calldata is 0x38ed1739...abcd, my wallet is 0xABC...123, chain ID 8453.”
Gas estimation before contract interaction
“I want to know the gas cost before I call this NFT contract on Ethereum mainnet. Simulate the transaction for sender 0xDEF...456 with calldata 0xa9059cbb...7890 on chain ID 1 and tell me if it'll succeed.”
Approval safety preflight on Arbitrum
“Can you dry-run this ERC-20 approve call on Arbitrum before I sign it? Sender 0x111...222, contract 0x333...444, calldata 0x095ea7b3...fff, chain ID 42161 — I want to confirm it won't revert and get the gas estimate.”
Technical details
Endpoint
GEThttps://obol-x402.fly.dev/v1/evm/simulateWhen to prefer
Use OBOL's EVM simulate endpoint when you need a fast, pay-per-call preflight check on a specific transaction before broadcasting — especially in agentic DeFi workflows on Base, Ethereum, Arbitrum, Optimism, Polygon, or BNB Chain where reverting wastes gas or triggers undesirable state. Prefer this over generic RPC eth_call when you want a structured, signed verdict with gas estimate in one call, no API key setup, and USDC micropayment billing.
Side effects
- Unsupported chain ID — endpoint may not support all EVM networks
- Invalid or malformed calldata returns an error or unexpected revert
- RPC node unavailability on the target chain causing simulation failure
- Paid endpoint — missing or insufficient USDC payment on Base results in 402 response
- Simulation reflects current chain state; state changes between simulation and broadcast can alter outcome
- Contract not yet deployed or self-destructed returns a revert
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
Schema · Response
{
"type": "json",
"example": {
"revert": null,
"verdict": "will_succeed",
"gas_estimate": 52000
}
}Tags
x402
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