an experimental option to provide “fallback autoptimized CSS and JS”; in some cases a cached version of the HTML links to autoptimized CSS/ JS that was already removed. if you enable that option, Autoptimize will try to intercept those requests and redirect them to fallback versions to limit the breakage. the option is default off for now, but might become default on at a later stage.
This plugin integrates with and extends Autoptimize. It integrates with criticalcss.com, a premium service which uses a “headless” browser to extract real critical CSS. That way it fully automates the extraction of high-quality critical CSS and the creation of rules for that critical CSS. It can work 100% automated, but also allows semi-automated jobs (where you enter a URL for which you want a specific rule, the power-up will do the rest) and manual rules (where you create the rule and add critical CSS yourself).
But time flies and it’s time for a new evolution; automated creation of critical CSS, using a deep integration with https://criticalcss.com using their powerful API! A first version of the plugin is ready and the admin-page looks like this (look to the right of this paragraph);
release as separate plugin on wordpress.org (shooting for April)
release as part of Autoptimize 2.5 (target mid 2018)
This new “criticalcss.com” power-up has been tested on a couple of sites already (including this little blog of mine) and we are now looking for a small group of to help beta-test for that first target. Beta-testers will be able to use criticalcss.com for free during the test (i.e. for one month). If you’re interested; head on up to the contact form and tell me what kind or site you would test this on (main plugins + theme; I’m very interesting in advanced plugins like WooCommerce, BuddyPress and some of the major themes such as Avada, Divi, Astra, GeneratePress, … ) and I’ll get back to you with further instructions.
So although I am taking things rather slowly, I am in fact still working on Power-Ups for Autoptimize, focusing on the one most people were asking for; critical CSS. The Critical CSS Power-Up will allow one to add “above the fold”-CSS for specific pages or types of pages.
The first screenshot shows the main screen (as a tab in Autoptimize), listing the pages for which Critical CSS is to be applied:
The second screenshot shows the “edit”-modal (which is almost the same when adding new rules) where you can choose what rule to create (based on URL or on WordPress Conditional Tag), the actual string from the URL or Conditional Tag and a textarea to copy/ paste the critical CSS:
The next step will be to contact people who already expressed interest in beta-testing Power-Ups, getting feedback from them to improve and hopefully make “Autoptimize Critical Css” available somewhere in Q3 2016 (but no promises, off course).