• First Visual Reaction • „Critical Path“ • Optimisation • Prioritize assets Time to First Paint https://github.com/sitespeedio/browsertime/blob/master/ browserscripts/timings/firstPaint.js
• Primary Content is Visible • above-the-fold text • e.g. product image • „Soft metric“ Time to First Meaningful Paint https://docs.google.com/document/d/ 1BR94tJdZLsin5poeet0XoTW60M0SjvOJQttKT-JK8HI/view#heading=h.yi0gbyc627x1
Google PageSpeed Insights • Analyses rendering • Critical path • SEO relevant • Cons • Not open source (any more) • Google API-Key required • Pre-RWD • Aggressive mobile rules
WebPageTest • Father of the SpeedIndex • Solid results • Records video • Online results • Cons • Confusing user interface • Messy selfhosting (Windows) https://www.webpagetest.org/