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agent402.tools Cheapest Rail Now
x402
agent402.tools Cheapest Rail Now is a paid API for AI agents from agent402.tools, paid per call via x402, $0.009/call, status unknown (last checked 2026-10-29).
Returns live gas prices across Ethereum and major L2s side-by-side, Base gas tiers, a fee estimate for a given transaction type, and ETH spot price to help an agent pick the cheapest chain to transact on right now.
Price / call$0.009
Success—
StatusUnknown
How this service works
Where should an agent transact this minute? Live gas on Ethereum + every major L2 side by side, Base gas tiers, a fee estimate for your transaction type, and ETH spot to price it all in dollars. Cheapest rail right now skill pack: one x402 payment runs 4 underlying tools (l2-gas-comparison, gas-snapshot, gas-estimate, crypto-price); partial-success per step.
Output
A bundled response containing real-time gas prices for each requested chain, Base-specific gas tiers, a transaction fee estimate in USD/ETH, and the current ETH spot price — enabling direct cost comparison to choose the cheapest chain to transact on.
Example use cases
Example prompt
“Check live gas prices across Ethereum, Base, Arbitrum, Optimism, and Polygon right now and tell me which chain is cheapest to transact on, including the ETH spot price and a fee estimate.”
Technical details
Endpoint
POSThttps://agent402.tools/api/skill/cheapest-rail?utm_source=zero.xyzWhen to prefer
Use this endpoint when an agent needs to dynamically route an on-chain transaction to whichever network has the lowest gas cost at that moment, or when displaying fee comparisons across Ethereum and L2s to a user before they sign a transaction. Prefer this over manual RPC polling when you need a single bundled view of gas + ETH price across multiple chains simultaneously.
Side effects
- Invalid or unsupported chain name in networks parameter returns an error or omits that chain
- Network connectivity issues fetching live gas data may result in stale or partial results
- Payment failure (insufficient USDC or x402 protocol error) blocks the call
- ETH price feed outage may affect USD cost estimates
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| networks | string | Comma-separated chains to compare (default: ethereum,base,arbitrum,optimism,polygon) |
Output
Schema · Response
{
"type": "json",
"example": {
"args": {
"networks": "ethereum,base,arbitrum,optimism,polygon"
},
"pack": "cheapest-rail",
"steps": [
{
"ok": true,
"slug": "l2-gas-comparison",
"result": {}
},
{
"ok": true,
"slug": "gas-snapshot",
"result": {}
},
{
"ok": true,
"slug": "gas-estimate",
"result": {}
},
{
"ok": true,
"slug": "crypto-price",
"result": {}
}
],
"summary": "4/4 steps succeeded"
}
}Tags
x402
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