AI agents are getting good at deciding what data they need. What they're bad at is the human paperwork around getting it: creating accounts, clicking email confirmations, pasting API keys, entering a credit card. Every one of those is a wall an autonomous agent can't climb on its own.
x402 removes that wall. It's an open payment protocol: the server answers 402 Payment Required
, the client pays a few cents in USDC on-chain, and the request goes through — no account, no key, no human. So I built a farm of APIs designed to be consumed exactly that way.
Base URL: https://api.x-402.online/
— the root returns a machine-readable JSON catalog, and there's an /openapi.json
/llms.txt
for agents.
53 endpoints, all pay-per-call in USDC (from $0.005), settled on Base (also accepts Polygon & Arbitrum):
The friction is the value: these wrap sources that need signup, keys, or heavy parsing (XBRL, registries) and expose them as one clean, payable call.
import { wrapFetchWithPaymentFromConfig } from "@x402/fetch";
import { ExactEvmScheme } from "@x402/evm";
import { privateKeyToAccount } from "viem/accounts";
const account = privateKeyToAccount(process.env.AGENT_KEY);
const fetchPaid = wrapFetchWithPaymentFromConfig(fetch, {
schemes: [{ network: "eip155:8453", client: new ExactEvmScheme(account) }],
});
// The wrapper handles the 402 -> sign -> retry automatically.
const res = await fetchPaid("https://api.x-402.online/v1/us/snapshot?ticker=AAPL");
console.log(await res.json());
The agent's wallet just needs USDC on Base. No gas needed on the client side — the facilitator settles.
Real on-chain payments are going through today (verifiable on BaseScan). If you're building agents that need company data, web extraction, or open-data lookups without the account/key dance, point them at https://api.x-402.online/
and let them pay their own way.
Feedback welcome — happy to add endpoints agents actually ask for.