Optimizing webpage: a real life case study – baseline

Optimizing webpage: a real life case study – baseline

Over the next couple of weeks I will be working on improving this site's performance. But to do that, it's best to start with a baseline measurements, so we know what we are up against.



(basically lighthouse)

The big four:

  • performance: 87
  • accessibility: 100
  • best practices: 87
  • SEO: 100

Certain detailed metrics and info:

  • FCP: 2.0s
  • Speed Index: 3.8s
  • LCP: 3.6s
  • Time to Interactive: 3.0s
  • Total Blocking Time: 150ms
  • CLS: 0.006
  • Links to cross-origin destinations are unsafe (Twitter&Github links are without noopener and noreferrer attrs)
  • Browser errors were logged to the console


CLS Desktop: 0.035
CLS Mobile: 0


  • LCP: 3.056s
  • CLS: 0.003
  • Total Blocking Time: 0
  • First Byte Time: 36/100
  • Use progressive JPEGs: 0/100
  • Leverage browser caching of static assets: 88/100; FAILED - (No max-age or expires) - https://pwisniewski.pl/members/api/site/


It's not great, it's not terrible ☢️️. CLS is consistently green, most other metrics are either green or close to it. There are some concerns with LCP, which I will try to address, and some minor issues that can provide relatively quick and easy gain - i.e. minifying stylesheet (which, admittedly, surprised me; I'm using Ghost CMS here, and thought it would handle this itself) and taking care of some wild console errors.

I wonder how well can I fix it? 🤔

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