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#001Target: High-Growth SaaS Landing Page (Next.js / Tailwind)•March 2026
Website Autopsy #001: A Full Mobile Performance Teardown
Mobile LCP5.4s (Failed)
Total DOM Elements3410
Total Page Weight6.8MB
Primary Bottleneck Discovered
Video hero background (4.2MB MP4) was loaded eagerly without preload controls, starving bandwidth from the Largest Contentful Paint text node.
User Experience Observation
Mobile viewport froze for 410ms on initial scroll as 18 unbundled tracking tags executed simultaneously on the main thread.
VitalsSniper PRO Forensic Telemetry:
VitalsSniper PRO surfaced 3,410 DOM elements, flagged the 4.2MB video payload, and exported a client proposal PDF card in under 50ms.
Actionable Optimization Roadmap
- Replace autoplay video background with responsive static WebP poster on mobile viewports.
- Offload third-party tracking scripts to a web worker via Partytown or defer execution past initial input.
- Flatten 28 nested wrapper DIVs into a single CSS grid container.
Run this exact diagnostic on any live website
VitalsSniper PRO inspects live tabs in 50ms and outputs white-label client tear sheets.