Page Optimization provides two Page Optimization 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 Page Optimization 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 Page Optimization requests/month. LiteSpeed Server users get up to 3800 additional free requests/month. 5000 requests may be purchased for 3000 credits.


Monthly free quota for Page Optimization requests
Tier Free Quota
200 requests
LiteSpeed Server
1,000 requests
LiteSpeed Enterprise
2,000 requests Hosting Partner
4,000 requests

* See Pricing page for description of tiers.

Monthly Subscriptions

Purchase additional monthly quota
Product Cost
10,000 requests
5,000 credits/month
20,000 requests
8,000 credits/month
30,000 requests
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 requests
3,000 credits

Please see the Pricing Page for details.

Join Forces with

Team up with! 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 users. It’s a win-win!