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MobileNetworkingCore Web Vitals

Why Mobile Speed Scores Lag (and How to Close the Gap)

A practical action plan for eliminating the delta between your mobile and desktop Lighthouse scores with network shaping, routing, and UI trade-offs.

Published October 8, 2024Updated January 2, 20257 min read

Key Takeaways

  • 1Simulated mobile tests must be part of CI to stay honest.
  • 2Design density is a mobile performance lever, not just an aesthetic choice.
  • 3Routing and DNS strategy can reclaim hundreds of milliseconds instantly.

Throttle like Chrome does

Use Chrome's `Slow 4G / 4x CPU` profile or Lighthouse's simulated mobile to mimic harsh realities. Anything less optimistic is vanity testing.

Pair that with MakeWebsite.fast multi-location tests so you understand how packet loss in São Paulo or Jakarta affects the same build.

  • Bake network shaping into CI, not just local debugging
  • Benchmark CPU-bound components and refactor the slowest hooks

Streamline interaction density

Mobile layouts frequently ship the same React tree as desktop. Collapse carousels, lazy load tabs, and prefer server actions for chatty workflows.

Audit interaction cues. High-density UI leads to more input latency, which drags INP along with general speed perception.

Route traffic intelligently

Adopt regional hosting or edge rendering so mobile TTFB stays under 200ms globally. Static assets should never cross an ocean.

If you can't move origins yet, at least optimize DNS with Anycast and preconnect to every third-party that survives your performance budget review.

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Frequently Asked Questions

Should mobile score ever match desktop?+

Matching is rare, but you should target <10 point delta. Anything larger signals CPU or routing debt.

Do PWAs fix mobile performance by default?+

Service workers help repeat visits, but you still need lean bundles and disciplined rendering.

M

MakeWebsite.fast Field Notes

Technical Analysis Team

Real-world performance insights from analyzing production websites. We focus on practical solutions that deliver measurable improvements.

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