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🔬 Style.Tools FEO widget - DevTools for Frontend Optimization (FEO)
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Style.Tools FEO Widget

A free Frontend Optimization (FEO) widget that works offline and for pages behind a login.

  • extract critical CSS
  • CSS editor
  • CSS beautify
  • CSS minify / optimization
  • repair broken CSS
  • remove unused CSS
  • remove duplicate CSS
  • PostCSS plugins: autoprefixer
  • CSS lint
  • CSS analysis

Documentation is available on the


Visit to install the widget or copy the following widget code in the browser console.

!function(r,a,k,l,f,g,b,m){function n(c,b,d){;b&&(r.onmessage=b);d&&a.addEventListener("securitypolicyviolation",d);a.write(c);a.close()}f="";g="Style.Tools";var c=a.createElement("script");c.src=f+"x.js";c.onerror=function(){function p(d){if(c=d?d.violatedDirective:0){if("script-src"==c||m)return;m=1;b&&l(b)}if(!q){var h=f+"#"+a.location;a.getElementById("e").innerHTML='<h2 style="color:red;">'+g+(c?' blocked by CSP <font color="blue">'+c+"</font>":" failed to load")+
'.</h2><h3>Redirecting <a href="'+h+'">'+h+"</a>...</h3>";b=k(function(){a.location.href=h},3E3)}}var q;n("<h2>Loading "+g+" via Service Worker...</h2><iframe src="+f+'go height=50></iframe><p id="e"></p>',function(a){q=1;b&&l(b);n("<script>""\x3c/script>")},p);b=k(p,2E3)};a.head.appendChild(c)}(window,document,setTimeout,clearTimeout);

Google Performance Scores

Style.Tools FEO Widget enables to resolve the remove unused CSS penalty in Google's performance score on the basis of pure CSS.

Google Performance Scores

For website and SEO tests, visit

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