In a New York Minute
summary
Median pages ship 561 KB of JavaScript with about 35% unused (p75 ≈ 857 KB; p90 unused ≈ 45%), and third‑party JS is ~63% of JS (median 292 KB) with 12% uncompressed and only ~7% deferred. Images cause 70% of LCP and 44% of images are lossless; hero images need ≈144 KB on 3G to hit a 2.5s LCP. HTTP Archive and the Web Almanac power the data, WebPageTest shows visual Speed Index and side‑by‑side video comparisons and offers one‑click no‑code experiments (async/defer, preload) to test fixes.
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chapters (15)
- 0:00Introduction and welcome
- 4:40What is a New York Minute
- 6:33The evolution of the Internet
- 9:14Mobile-first web performance
- 10:20JavaScript usage trends
- 13:54Async vs defer attributes
- 17:14Resource hints and third-party JS
- 21:46Total blocking time and long tasks
- 23:51JavaScript discipline and frameworks
- 24:16Image formats and LCP challenges
- 28:18Lazy loading and oversights
- 30:39Why measurement matters
- 31:52WebPageTest features and metrics
- 34:30Raising web performance literacy
- 36:47Q&A begins with Vitaly
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