Gas snapshot (slow / standard / fast)

Live gas price snapshot for a chain - slow / standard / fast tiers in gwei, plus the latest base fee. Send POST /api/gas-snapshot with no required fields (1 optional) and pay $0.005 per call over x402 or MPP (there is no free tier). It returns a JSON object with network, chainId, baseFeeGwei, slow, standard and 1 more.

Sampled from eth_feeHistory (last 4 blocks, 25th/50th/90th percentile priority fees). Use to estimate before broadcasting a transaction from another tool.

Category: Crypto & onchain data · Tags: crypto gas fees evm transaction · Also found as: gas

TRY IN PLAYGROUND →

Parameters

Example request

curl -i -X POST https://agent402.tools/api/gas-snapshot \
  -H "Content-Type: application/json" \
  -d '{"network":"base"}'

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

Example response

{
  "network": "base",
  "chainId": 8453,
  "baseFeeGwei": 0.005,
  "slow": {
    "priorityFeeGwei": 0.001,
    "totalGwei": 0.006
  },
  "standard": {
    "priorityFeeGwei": 0.002,
    "totalGwei": 0.007
  },
  "fast": {
    "priorityFeeGwei": 0.005,
    "totalGwei": 0.01
  }
}

From an MCP client

catalog.call {
  "slug": "gas-snapshot",
  "params": {
    "network": "base"
  }
}

The hosted connector at https://agent402.tools/mcp needs a payment for gas-snapshot; 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/gas-snapshot 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/gas-snapshot", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({
    "network": "base"
  }),
});

Part of these workflows

Gas snapshot (slow / standard / fast) is one step in these 4 skill packs, each sold as a single call:

• Agent wallet readiness check - One call answers 'can this wallet pay right now?' - USDC balances on Base AND Solana, live Base gas, and a ready-to-share Coinbase Onramp funding link if it's running dry.
• 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.
• DeFi dashboard - DeFi market overview: total TVL, ETH price, Base gas, and global crypto stats in one call.
• Gas optimizer - Find the cheapest gas right now: Base gas, Ethereum gas, Base fee estimate, and ETH price for USD conversion.

Related tools