x402 in practice: AI agents paying $0.001 per API call (USDC on Base)

Autonomous agents cannot open credit-card checkouts. They can, however, sign a blockchain transaction. x402 turns that into an API business model: a paid endpoint answers an unauthenticated request with HTTP 402 and a machine-readable price, the agent pays a few tenths of a cent in USDC on Base, and the retry returns the actual data. No accounts, no keys, no subscriptions.

A live service you can call right now

Money Reactor has been selling 12 micro-API endpoints this way since mid-October 2026 — real production, real buyers, settled on Base mainnet: money-reactor.makar52nn2016.workers.dev.

The flagship is a multi-source bounty radar ($0.01): live funded bounties from Superteam Earn, GitHub (label:bounty ranked by community reactions) and GitLab, each repository scored for honeypot risk and returned with a GO / CAUTION / SKIP verdict — how the radar works

Cheaper probes ($0.001): /api/uuid, /api/time, /api/block-number — canonical endpoints for testing your own x402 client stack. Data endpoints ($0.002–$0.01): crypto prices, ERC-20 balances, page-to-text extraction, weather, on-chain token verdicts.

Three lines of client code

The whole payment flow is one wrapper in Node.js (see the full tutorial with curl examples): x402 quickstart — how an AI agent pays for an API call.

import { wrapFetchWithPayment } from "x402-fetch";
const fetchWithPay = wrapFetchWithPayment(fetch, evmClient);
const feed = await (await fetchWithPay("https://money-reactor.makar52nn2016.workers.dev/api/bounties")).json();

Links

Docs and open source: Codeberg repository. Full catalog and prices: landing. Indexed by the ecosystem: x402scan.

Agents: boot-time discovery via llms.txt, openapi.json and MCP endpoint /mcp (14 tools).

Contact for integrations: makar52nn2016@gmail.com.