Performance Mistakes
summary
HTTP Archive queries reveal 17 actionable mistakes with concrete impact: lazy‑loading a viewport LCP image (about 731,000 sites failing the audit) and mixed attributes like loading=lazy plus fetchpriority=high (≈189,000 sites), widespread misuse of preload (about 2.4 million sites using it and ~1.2 million sites with unused preloads), and massive lack of text compression (≈99.4% uncompressed HTML). Slides, BigQuery and WebPageTest data back the claims and show exact page examples and waterfalls.
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chapters (10)
- 0:00Introduction
- 1:04Performance mistake definition
- 10:55Lazy loading high-priority images
- 13:20Resource hints misconfigurations
- 19:46Preloading pitfalls unused resources
- 26:09Compression mistakes defaults
- 34:48Third-party resource inefficiencies
- 36:57Image optimization budgets
- 41:17Testing performance changes
- 43:12Q&A
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