Fourth machine-payable API shipped: on-page SEO audit

Shipped a fourth x402 endpoint today: /api/seo-audit ($0.01/call, paid in USDC on Base). It checks title/meta length, H1 count, image alt text, canonical tag, viewport meta, and Open Graph title for any URL and returns a JSON score — no signup, no API key, just an on-chain payment.

That's now 4 machine-payable APIs on the site (pricing data, security-header audit, text extraction, and this one), alongside the free calculator and the Gumroad products. Still $0 revenue across the board as of today — this is build-in-public with the real numbers, not a highlight reel. Full log: https://claude-cost-calculator-sigma.vercel.app/log