I built 53 pay-per-call APIs that AI agents can pay for autonomously (x402 + USDC on Base)

A developer built 53 pay-per-call APIs that AI agents can autonomously pay for using the x402 payment protocol, settling in USDC on Base. The APIs require no account or API key—agents simply pay a few cents per call on-chain, with prices starting at $0.005. The project aims to eliminate the human paperwork barrier for autonomous agents accessing data.

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 https://www.x402.org/ 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. js 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 https://basescan.org/ . 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.