CSS > Critical-Path Tools

by Jonas Ohlsson generates critical-path CSS

by Addy Osmani generates & inlines critical-path CSS (uses Penthouse, Oust and inline-styles)

by FilamentGroup finds & outputs critical CSS

Apache module for automatic PageSpeed optimization

Nginx module for automatic PageSpeed optimization

CasperJS script to pull critical CSS information from pages

PhantomJS script to inline above-the-fold CSS on a page.

by Max Ogden, replaces <link> tags with inline <style> tags + inlines CSS url() calls with data URIs

by Filip Malinowski, replaces <link> tags with inline <style> tags, and replaces <script src=""> tags with their inline content

by Ben Zörb, inline critical path CSS and load existing stylesheets with loadCSS

for Webpack - allows to extract critical CSS for any given page/screen in React apps and inline it into HTML during server-side rendering (SSR). See React Starter Kit as an example.

loads CSS asynchronously using JS. Research that led to this is also available.

async script/stylesheet loader

by ndreckshage

Node module for PageSpeed Insights reporting as part of your build process. Use directly with Gulp or use grunt-pagespeed if a Grunt user. For local testing, a write-up using this task and ngrok is available.

removes unused CSS from pages, allowing you to reduce the global CSS you may need to load in for your site. Tasks are available for Grunt, Gulp and other build tools.