ToolVet
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Gas Fees

by Blackwood State Gas Fees in Onchain & crypto

x402 APIPassing, checked 3 h ago

Use when you need a gas price or fee estimate before a transaction on Ethereum, Base or Solana, or to compare gas fees across chains. Do not use for gas units of a given transaction, gas history or chains beyond Ethereum, Base and Solana. Returns JSON with live gas fees for Ethereum and Base (base fee, slow, standard and fast EIP-1559 priority and max fees in gwei, transfer cost) and Solana priority fees, in one call for 0.003 USDC per call. Typical response time 1500 ms (p95). Category: Data.

POST
https://x402-gateway.blackwoodstate8.workers.dev/v1/gas-fees
Price
$0.003
per call in USDC
Uptime
100%
last 30 days
Response time
1.3 s
1.3 s slowest 5%
Last check
Passed
3 h ago, next any minute now

Run a free test callHow to call it

Reliability

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Status and outage history · Atom feed · Watch with other listings

How to call it

POST https://x402-gateway.blackwoodstate8.workers.dev/v1/gas-fees

Each call costs $0.003 in USDC on Base, paid with the request over x402.

Run a free test callOne unpaid request, the way an agent sends it. You see the payment challenge it gets back. Nothing is charged.

Example request

From the listing.

POST https://x402-gateway.blackwoodstate8.workers.dev/v1/gas-fees
content-type: application/json

{}

Parameters

ParameterTypeRequiredDescription
chainsarray of stringNoChains to read (ethereum, base and solana when omitted), e.g. ["base", "ethereum"]

Example response

The provider's example. We can't check it without paying.

Example response, 59 lines
{
  "base": {
    "baseFeeGwei": 0.005,
    "blockNumber": 52750593,
    "chainId": 8453,
    "gasPriceGwei": 0.006,
    "maxFeeGwei": {
      "fast": 0.015,
      "slow": 0.01,
      "standard": 0.011
    },
    "nextBaseFeeGwei": 0.005,
    "priorityFeeGwei": {
      "fast": 0.005,
      "slow": 0,
      "standard": 0.001
    },
    "transferCostEth": {
      "fast": 2.1e-7,
      "slow": 1.05e-7,
      "standard": 1.26e-7
    }
  },
  "ethereum": {
    "baseFeeGwei": 0.0413101,
    "blockNumber": 26216462,
    "chainId": 1,
    "gasPriceGwei": 0.0413101,
    "maxFeeGwei": {
      "fast": 1.07495,
      "slow": 0.0749717,
      "standard": 0.0762873
    },
    "nextBaseFeeGwei": 0.0374734,
    "priorityFeeGwei": {
      "fast": 1,
      "slow": 0.000024942,
      "standard": 0.00134048
    },
    "transferCostEth": {
      "fast": 0.0000217869,
      "slow": 7.87465e-7,
      "standard": 8.15091e-7
    }
  },
  "note": "Gas in gwei. EIP-1559 tiers are the median 10th, 50th and 90th percentile priority fees of the last 20 blocks; max fee = 2 x next base fee + priority fee; transfer cost is a 21,000-gas ETH transfer. Solana: priority fee levels in micro-lamports per compute unit, on top of 5,000 lamports per signature.",
  "solana": {
    "baseFeeLamportsPerSignature": 5000,
    "priorityFeeMicroLamportsPerCu": {
      "high": 50000,
      "low": 0,
      "medium": 2673,
      "min": 0,
      "veryHigh": 2000000
    },
    "slot": 458268792
  },
  "updatedAt": "2026-10-18T02:28:53.602Z"
}

Call it from code

The curl command shows the payment challenge. The JavaScript and Python versions pay and call, and never pay more than $0.003.

curl: see the payment challenge
# bash or zsh: see the payment challenge. Nothing is charged.
curl -sS -g -i -X POST 'https://x402-gateway.blackwoodstate8.workers.dev/v1/gas-fees' \
  -H 'content-type: application/json' \
  --data-raw '{}'

# x402 v2 sends the challenge base64-encoded in the PAYMENT-REQUIRED header (v1 sends it in the body).
# To read the header:
curl -sS -g -o /dev/null -D - -X POST 'https://x402-gateway.blackwoodstate8.workers.dev/v1/gas-fees' \
  -H 'content-type: application/json' \
  --data-raw '{}' \
  | grep -i '^payment-required:' | cut -d' ' -f2 | tr -d '\r' | base64 --decode
JavaScript: pay and call
// npm i @x402/fetch @x402/evm viem
import { wrapFetchWithPayment, x402Client } from "@x402/fetch";
import { registerExactEvmScheme } from "@x402/evm/exact/client";
import { privateKeyToAccount } from "viem/accounts";

// Pays at most $0.003 per call.
const client = new x402Client().setSpendControls({ maxAmountPerPayment: "$0.003" });
registerExactEvmScheme(client, { signer: privateKeyToAccount(process.env.EVM_PRIVATE_KEY) });
const pay = wrapFetchWithPayment(fetch, client);

// Not sure it's safe to pay? ToolVet checks it first for $0.005. Pay for that from a separate
// client: this one is capped at $0.003 per payment. GET https://toolvet.app/api/v1/check?url=https%3A%2F%2Fx402-gateway.blackwoodstate8.workers.dev%2Fv1%2Fgas-fees&method=POST
const res = await pay("https://x402-gateway.blackwoodstate8.workers.dev/v1/gas-fees", {
  method: "POST",
  headers: { "content-type": "application/json" },
  body: JSON.stringify({}),
});
console.log(res.status, await res.text());
Python: pay and call
# pip install "x402[requests,evm]"
import os
from eth_account import Account
from x402 import x402ClientSync
from x402.http.clients import x402_requests
from x402.mechanisms.evm import EthAccountSigner
from x402.mechanisms.evm.exact.register import register_exact_evm_client

# Pays at most $0.003 per call.
client = x402ClientSync().set_spend_controls({"max_amount_per_payment": "$0.003"})
register_exact_evm_client(client, EthAccountSigner(Account.from_key(os.environ["EVM_PRIVATE_KEY"])))

with x402_requests(client) as session:
    res = session.post(
        "https://x402-gateway.blackwoodstate8.workers.dev/v1/gas-fees",
        json={},
    )
    print(res.status_code, res.text)

Security scan

No findings

We scan names, descriptions and tool definitions for hidden instructions and other prompt-injection patterns.

Recent checks

WhenResultHTTPTimePrice
3 h agoPassed4021.3 s$0.003