Building a High-Performance Site Analyzer with Astro, React, and Node.js Performance Hooks

Precision Diagnostics: How We Built the Deltum Site Checker Most website "health checkers" are either bloated, marketing-heavy, or hide their most valuable data behind a sign-up wall. At Deltum , we believe that digital systems should be transparent and built to last. To support this, we built a Site Checker —a real-time diagnostic tool designed to give developers and founders an immediate, high-fidelity look at their site’s connectivity, security, and performance. Here is a look at the technical architecture behind it. The Goal: Accuracy Without Overhead We needed the tool to be three things: Instant : No waiting for full page renders. Accurate : Measuring raw server response, not just browser-level "perceived" speed. Informative : Auditing security headers that actually matter (CSP, HSTS, etc.). The Tech Stack Following our core principle of "Fewer dependencies, stronger systems," we utilized our standard stack: Framework : Astro (using SSR mode on Vercel) UI Architecture : React Isl