# SiteSignal

> Pay-per-call web utilities for AI agents via x402 (USDC on Base, no API key).

## Endpoints
- [GET /v1/email-security](https://sitesignal-api.vercel.app/v1/email-security?domain=stripe.com): $0.005 USDC. Email-auth & deliverability audit for a domain: MX/provider, SPF (lookup count, all-qualifier), DMARC policy, DKIM on 18 common selectors, MTA-STS, TLS-RPT, BIMI, CAA. Returns A–F grade, score and copy-paste DNS fixes.
- [GET /v1/page-extract](https://sitesignal-api.vercel.app/v1/page-extract?url=https%3A%2F%2Fexample.com): $0.003 USDC. Fetch any public web page and return clean Markdown plus title, meta description, Open Graph, headings outline, JSON-LD types and link summary. Built for LLM agents (max 20k chars).
- [GET /v1/seo-audit](https://sitesignal-api.vercel.app/v1/seo-audit?url=https%3A%2F%2Fexample.com): $0.01 USDC. On-page SEO + AI-readiness audit of a URL: 17 weighted checks (title, meta description, H1, canonical, indexability, OG/Twitter, alt text, JSON-LD, content depth, speed, robots.txt, sitemap.xml, llms.txt). Returns 0–100 score, grade and top 5 fixes.

## Docs
- [OpenAPI](https://sitesignal-api.vercel.app/openapi.json)
- [Free email grade](https://sitesignal-api.vercel.app/free/email-grade?domain=example.com)
- [Free SEO score](https://sitesignal-api.vercel.app/free/seo-score?url=https://example.com)