{
  "service": "txpreflight",
  "what": "Base mainnet transaction preflight: does this call revert, what gas will it use, what EIP-1559 fees are sane right now, and what will it cost in ETH and USD.",
  "paid_endpoint": "POST /preflight  (x402, $0.01)",
  "free_endpoints": [
    "GET /",
    "GET /health"
  ],
  "input_example": {
    "from": "0x4200000000000000000000000000000000000006",
    "to": "0xd9aAEc86B65D86f6A7B5B1b0c42FFA531710b6CA",
    "data": "0x095ea7b300000000000000000000000011111111111111111111111111111111111111110000000000000000000000000000000000000000000000000000000000000001",
    "urgency": "normal"
  },
  "notes": "Simulation only, against the latest block. Base chain. Foundry-style: use it as a guard step before signing."
}