Latest block number

The latest block number on Ethereum, Base, Polygon, Arbitrum, or Optimism. The cheapest possible on-chain read - the hello world of paid chain access. Keyless multi-endpoint failover. ?network=base

Input

Example output

{
  "network": "base",
  "blockNumber": 27000000,
  "hex": "0x19bfcc0"
}

Try it - see the 402 challenge (free)

curl -i "https://agent402.tools/api/block-number?network=base"

The response is HTTP 402 Payment Required with exact payment requirements. Any x402 v2 client pays automatically and retries:

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();
registerExactEvmScheme(client, { signer: privateKeyToAccount(KEY) });
const payFetch = wrapFetchWithPayment(fetch, client);

const res = await payFetch("https://agent402.tools/api/block-number?network=base");

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