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Gas Price Estimator — Multi-Chain EVM Gas Fees (x402)
x402
Gas Price Estimator — Multi-Chain EVM Gas Fees (x402) is a paid API for AI agents from freetier-agent-api.pages.dev, paid per call via x402, $0.0015/call, status unknown (last checked 2026-10-30).
Returns current gas price estimates and ERC-20 transfer costs across major EVM chains, ranking them cheapest to most expensive
Price / call$0.0015
Success—
StatusUnknown
How this service works
Invoice-to-JSON, on-chain tools (transaction explainer + payment check, wallet profile, contract ABI, ERC-20 token risk), company contacts and web-to-RAG for AI agents. Pay per call with x402 (USDC on Base). No signup, no API key.
Output
Returns a JSON object with an array of chain entries (each including block number, chain name, chain ID, native coin, gas price in gwei, and estimated ERC-20 transfer cost in gas units, USD, and native token), plus a ranked list of chains from cheapest to most expensive and a 'cheapestForUsdcTransfer' field indicating the optimal chain.
Example use cases
Cheapest chain for USDC payment routing
“I need to send USDC to a vendor — which of Ethereum, Base, Arbitrum, Optimism, or Polygon has the lowest gas fees right now for an ERC-20 transfer, and what will it cost me in USD?”
Real-time gas dashboard for all EVM chains
“Give me the current gas prices across all supported EVM chains — I want the gwei price, the USD cost of an ERC-20 transfer, and how they rank from cheapest to most expensive.”
Base vs Arbitrum gas comparison
“Compare current gas fees on Base versus Arbitrum only — what's the gas price in gwei on each and how much would an ERC-20 token transfer cost in USD on each chain?”
Technical details
Endpoint
GEThttps://freetier-agent-api.pages.dev/api/gas?utm_source=zero.xyzWhen to prefer
Use this endpoint when an AI agent needs to programmatically decide which EVM chain to use for a token transfer based on current gas costs, or when building a gas fee dashboard. It covers the five major EVM chains (Ethereum, Base, Arbitrum, Optimism, Polygon) in a single call. Prefer it over chain-specific RPC calls when you need cross-chain comparison without managing multiple providers. Requires pay-per-call with USDC via x402 — no API key needed.
Side effects
- Invalid chain name in 'chains' parameter returns an error or empty result
- Network latency causes stale gas price data for fast-moving chains like Ethereum mainnet
- x402 payment failure if USDC balance on Base is insufficient
- Cloudflare Pages cold-start latency on first request
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
Schema · Response
{
"type": "json",
"example": {
"chains": [
{
"block": 37000000,
"chain": "base",
"chainId": 8453,
"estimates": {
"erc20_transfer": {
"gas": 65000,
"usd": 0.0012,
"native": "0.00000039"
}
},
"nativeCoin": "ETH",
"gasPriceGwei": 0.006
}
],
"ranking": [
"base",
"optimism",
"arbitrum",
"polygon",
"ethereum"
],
"cheapestForUsdcTransfer": "base"
}
}Tags
x402
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