L2 gas comparison

Current gas snapshot across Ethereum + supported L2s (Base, Polygon, Arbitrum, Optimism), sorted cheapest-first. Send POST /api/l2-gas-comparison with no required fields (1 optional) and pay $0.002 per call over x402 or MPP (there is no free tier). It returns a JSON object with queriedAt, networks, cheapest and source.

Returns gas price in gwei, latest block number, chain id, and an isL2 flag per chain. Use to route a transaction to the cheapest viable L2 or to track L1→L2 gas spread.

Category: Crypto & onchain data · Tags: l2 gas cross-chain comparison routing

TRY IN PLAYGROUND →

Parameters

Example request

curl -i -X POST https://agent402.tools/api/l2-gas-comparison \
  -H "Content-Type: application/json" \
  -d '{"networks":["ethereum","base","arbitrum","optimism","polygon"]}'

Without payment this returns HTTP 402 Payment Required with the exact price for l2-gas-comparison; any x402 v2 or MPP client pays it and retries.

Example response

{
  "queriedAt": "2026-06-22T19:00:00.000Z",
  "networks": [
    {
      "network": "base",
      "chainId": 8453,
      "isL2": true,
      "gasPriceWei": "100000000",
      "gasPriceGwei": 0.1,
      "blockNumber": 22000000
    },
    {
      "network": "arbitrum",
      "chainId": 42161,
      "isL2": true,
      "gasPriceWei": "100000000",
      "gasPriceGwei": 0.1,
      "blockNumber": 300000000
    },
    {
      "network": "ethereum",
      "chainId": 1,
      "isL2": false,
      "gasPriceWei": "15000000000",
      "gasPriceGwei": 15,
      "blockNumber": 22000000
    }
  ],
  "cheapest": "base",
  "source": "alchemy"
}

From an MCP client

catalog.call {
  "slug": "l2-gas-comparison",
  "params": {
    "networks": [
      "ethereum",
      "base",
      "arbitrum",
      "optimism",
      "polygon"
    ]
  }
}

The hosted connector at https://agent402.tools/mcp needs a payment for l2-gas-comparison; the stdio package pays it from a wallet or from AGENT402_CREDITS_KEY. Local install: npx -y agent402-mcp.

Errors and behavior

• Every field is optional. An input the tool rejects returns an HTTP 4xx whose body carries error, tool, expected, required and example.
• A paid call that ends in any status of 400 or above is not charged over x402, MPP or a prepaid credits key: settlement is cancelled when the tool fails. The exception is a Tempo push credential, a transfer the buyer sent before the call: it settles before the tool runs, so if the tool then fails the payment is recorded as a refund owed to the paying wallet.
• Wallet-only: this tool reaches the network or stored state, so it has no proof-of-work tier. A prepaid card-credits key issued earlier (Authorization: Bearer a402_...) also pays it.
• A GET or HEAD to /api/l2-gas-comparison returns the same 402 quote, so the price can be read without a body.
• An Idempotency-Key header makes a retried paid call replay the first 200 instead of charging again (an answer larger than 1 MB is not replayed).

Paid call (JavaScript agent)

import { wrapFetchWithPayment } from "@x402/fetch";
import { x402Client } from "@x402/core/client";
import { registerExactEvmScheme } from "@x402/evm/exact/client";
import { privateKeyToAccount } from "viem/accounts";

const client = new x402Client();
client.setSpendControls?.(false); // keep your own spending ceiling in code
registerExactEvmScheme(client, { signer: privateKeyToAccount(KEY) });
const payFetch = wrapFetchWithPayment(fetch, client);

const res = await payFetch("https://agent402.tools/api/l2-gas-comparison", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({
    "networks": [
      "ethereum",
      "base",
      "arbitrum",
      "optimism",
      "polygon"
    ]
  }),
});

Part of these workflows

L2 gas comparison is one step in this skill pack, each sold as a single call:

• Cheapest rail right now - 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.

Related tools