Speculations about Web Performance
summary
Speculation Rules API lets sites ship a JSON rule set to prefetch or pre-render likely navigations; real deployments (WordPress, Shopify, Etsy) show measurable wins — Shopify reports 120–180 ms saved P75 LCP, Etsy cuts many TTFBs to near zero and scalemates reaches ~404 ms LCP — about 12% of page loads now use the feature in Chrome. Implementation uses link-rel prefetch/prerender, new pre-render until script mode, and server-side headers; risks include extra server/CDN load, stale state and analytics workarounds, with prefetch lower risk than full pre-render.
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chapters (12)
- 0:00Introduction and speaker bio
- 1:14Built-in browser performance
- 5:26JavaScript performance and yield
- 6:53The extensible web manifesto
- 11:13Speculation rules API
- 16:36Prerendering performance
- 18:06Implementation risks and issues
- 21:35Mitigation strategies
- 25:15Advanced speculation techniques
- 29:38Browser support and adoption
- 34:23Industry usage and conclusions
- 37:26Q&A and closing remarks
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