Notes from the Martin Splitt’s JavaScript SEO Office Hours on May 20th 2020

Google Cache Should Not be Used for Debugging

The Google cache will usually show the initial response HTML but may show the rendered HTML or an older version. The feature was designed as a fallback if a website has gone down, but it’s not actively supported and shouldn’t be used as a debugging tool.

Improve Page Load by Removing Unused JavaScript

You can use a number of tools and techniques to remove unused JavaScript and increase page load times, including Chrome dev tools, webpagetest, and tree shaking.

HTTP2 Won’t Improve Googlebot Rendering Speed

Googlebot doesn’t use HTTP2, so this won’t help improve Googlebot’s rendering speed.

Use Service Workers to Pre-fetch Resources

Service workers can be used to pre-fetch resources and improve page load for users.

Cache Control Headers are Ignored

Google usually ignores cache control headers because many resources are under-cached which would put a higher load on Google’s resources. You can use versioned filenames can be used to force Google to fetch an updated resource.