Wordpress LScache Plugin: Generate Critical CSS In Background issues
Last Updated on: Wed, 15 Apr 2026 00:00:02 Hey folks! I cannot use Generate Critical CSS In Background. When this is enabled, my website shows its code (unstyled content) for a split second when loading a page. Is there any way to solve this? Hi, In that case you will need to make it run in foreground. Best regards, Nevermind, its not the Critical CSS in Background that causes FOUC, its the Load CSS Asynchronously option. Ive read up the LiteSpeed documentation and as far as I understand having CSS in Background option ON should solve this issue. However, Its not working for me. As soon as I enable Load CSS Asynchronously, I get FOUC. I can hit refresh 20 times on my page but nothing changes, FOUC every single time. The plugin is connected to QUIC.cloud so can it be an issue on the QUIC side? Thanks Hi, as I understand having CSS in Background option ON should solve this issue. No, it should be Background OFF , if you read that from doc , then it must be wrong , I would appreciate if you can provide me the link of doc you read. so can it be an issue on the QUIC side? No, CCSS generation only requires domain key , if you got the domain key , it should work. and please check this wiki , it may give you some hint Best regards, Hi @CacheCrawler thank for the reply. I did try with: ON ? Load CSS Asynchronously ON ? Generate Critical CSS OFF ? Generate Critical CSS In Background This set up causes FOUC on every single load. It is more pronounced in Firefox but also visible in Chrome. I have just re-tested it again and the ONLY way I can get rid of FOUC is by turning off Load CSS Asynchronously. So yes, I still have the issue ongoing. Here is where I read that Background CSS set to ON might solve the issue. https://blog.litespeedtech.com/2018/06/20/critical-css-and-litespeed-cache/ Hi, If you read few lines below , you will see it says The only drawback to this approach is that the first visitor is likely to get the FOUC. anyway , have you checked my previous reply provided link ? it will show you the way how to verify if CCSS is generated/inserted. Do you see CCSS rule in it ? Best regards, Yes, I do see the rules inserted between the tags. Once again: Load CSS Asynchronously ? ON Generate Critical CSS ? ON Generate Critical CSS In Background ? OFF Purged all LSCache then reloaded the page a few times. CCSS ruleshows in the code. However, still having the FOUC issue. I am thinking it might be a browser cache issue as well. I tried clearing all but it doesnt seem to be working. I mean, it can be the issue, right? Hi, Could you please provide the report number ? you can get it from toolbox ?> report Best regards, Hi, Im going to mark this topic Resolved, due to lack of activity. If you still need help, please provide your Report Number, found in WP Admin > LiteSpeed Cache > Toolbox > Report. (Press the Send to LiteSpeed button and make note of the number.) Well be happy to reopen the topic if necessary. Thanks!
LiteCache Rush: Speed comes from using less, not from doing it faster
Reference