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Discussion on: My website now loads in less than 1 sec! Here's how I did it! ⚡

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markgoho profile image
Mark Goho

Lighthouse inspects cache-control headers, and if you don't have them set (or set properly) you will be penalized.

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joelbonetr profile image
JoelBonetR

You will always have caching (servers usually perform cache automatically by default) but the error you get on pagespeed about "Serve static assets with an efficient cache policy" is about resource cache headers (images, scripts, style sheets...) that implies cache lifetime. This means adding Cache-Control: max-age=31536000 (which is a 1 year lifetime cache).

BTW cache must speed up the downloaded resources, so logically (and practically) you must get more pagespeed score using a cache of 1 day than not using cache for example, but pagespeed request uses no-cache server request and avoids user/local cache, so the score will be the same using cache or not, that's what I wanted to mean .

The difference on pagespeed score about using 1 year cache lifetime on all assets and not using cache will be only about the weight of the error mentioned above. You can try solving all errors and performing all recommendations except this one and check how much it weights.

Another point to keep in mind is that if you are managing a web app which is constantly evolving and you set a 1 year lifetime cache, you'll probably need to purge the cache every time you deploy a version into production (recommended custom purge only for the assets you updated).