CSS Optimization

QUIC.cloud provides two services aimed at streamlining your site’s CSS: Critical CSS (CCSS) and Unique CSS (UCSS).

Critical CSS is the minimum CSS code necessary to style a page for the first paint. Pages with critical CSS inserted directly into the HTML avoid the dreaded FOUC, or Flash of Unstyled Content, when loading CSS asynchronously. Our CCSS service generates Critical CSS for your pages, and inserts it directly into the page’s HTML. Even if the CSS files are loaded more slowly than the page HTML, the first screen will still display fully formatted. This is because the necessary CSS was included in the HTML.

Unique CSS is the minimum CSS code necessary to style a page from start to finish. By including only the necessary CSS for the page and eliminating any unused CSS, file size is reduced and precious processing time is saved. Our UCSS service combines all of a page’s inline and external CSS into a single file, discarding any elements that are not in use by the current page.

Use our Critical CSS and Unique CSS services to load your pages properly formatted, near instantly!

How Critical CSS Works

Flash of Unstyled Content, as HTML loads before CSS is ready

Critical CSS avoids FOUC and loads the page properly styled

CCSS is the CSS needed to style content visible at first paint

<!doctype html>
     An Optimized Web Page
     <style type="text/css">
      (Your minified inline Critical CSS would be here)
     (Your markup)

CCSS is inserted directly into the page’s HTML, dramatically reducing the perceived load time, and ensuring content is loaded fully styled.

How Unique CSS Works

WordPress pages can have inline CSS and CSS from varied other sources

UCSS combines these into a single file and discards unused definitions

Page loads fast as CSS is processed quickly in this simplified form


Free for the first 200 CCSS or UCSS calculations/month. LiteSpeed Server users get up to 3800 additional free CSS calculations/month. 5000 CSS calculations may be purchased for 3000 credits.


Monthly free quota for Crital CSS and Unique CSS calculating
Tier Free Quota
200 calculations
LiteSpeed Server
1,000 calculations
LiteSpeed Enterprise
2,000 calculations
QUIC.cloud Hosting Partner
4,000 calculations

* See Pricing page for description of tiers.

Monthly Subscriptions

Purchase additional monthly quota
Product Cost
10,000 calculations
5,000 credits/month
20,000 calculations
8,000 credits/month
30,000 calculations
10,000 credits/month

Please see the Pricing Page for details.

Pay as You Go

Purchase one-time additional Critical CSS and Unique CSS quota
Product Quota Cost
1 Refill Unit
5,000 calculations
3,000 credits

Please see the Pricing Page for details.

Join Forces with QUIC.cloud

Team up with QUIC.cloud! If you are interested in donating a node, using our service in your own product development, or even if you are a CDN service interested in collaboration, we want to hear from you! In return, you will be helping your own customers and getting your name seen by our QUIC.cloud users. It’s a win-win!