FAQ

What is x402?

x402 is an open payment protocol for HTTP APIs. Instead of API keys, your client sends a small on-chain USDC payment with each request. No account, no subscription.

Do I need to sign up?

No. No account, no API key, no email. Just a wallet with USDC on Base.

What wallet do I need?

Any EVM-compatible wallet with USDC on Base. Most x402 clients (including x402-fetch) work with any viem-compatible signer.

How do I get USDC on Base Sepolia for testing?

Use the Circle USDC faucet. Free testnet USDC, no KYC.

What does the snapshot check?

HTTP response headers: HSTS, CSP, X-Frame-Options, X-Content-Type-Options, Referrer-Policy, Permissions-Policy. Plus presence of security.txt, robots.txt, sitemap.xml.

Does it run JavaScript or render the page?

No. It performs a plain HTTP GET and inspects the response headers only. No browser, no JavaScript execution.

Can I scan private or internal URLs?

No. The API only scans publicly reachable URLs over HTTP/HTTPS. Private IPs, localhost, and internal hostnames are rejected.

Is the result deterministic?

Yes. The same URL at the same point in time will return the same result. There is no AI scoring, no opaque logic.

What is the rate limit?

No artificial rate limit. Each call requires payment, which is the natural rate control.

I found a bug or have a question.

See Support.