Deep uptime & health report from one socket-level HEAD probe: DNS/TCP/TLS/TTFB timing waterfall, TLS certificate (issuer, expiry countdown, trust status), HTTP/2 support via ALPN, server IP + hosting location, CDN detection, redirect chain, caching + security response headers, compression, server clock skew. On failure, says exactly which phase died. Everything a monitor needs in one deterministic call — no page download.