PUBLIC MARKS with tag webperf

Critters is a plugin that inlines your app's critical CSS and lazy-loads the rest.

This article discusses performance best practices for fonts. There are a variety of ways in which web fonts impact performance: Delayed text rendering: If a web font has not loaded, browsers typically delay text rendering. In many situations, this delays First Contentful Paint (FCP). In some situations, this delays Largest Contentful Paint (LCP). Layout shifts: The practice of font swapping has the potential to cause layout shifts and so impact Cumulative Layout Shift (CLS). These layout shifts occur when a web font and its fallback font take up different amounts of space on the page.

A Service Worker that monitors network requests to estimate bandwidth and RTT

Delivering less JavaScript can mean less time in network transmission, less spent decompressing code and less time parsing and compiling this JavaScript.

a linting tool for the web: accessibility, speed, security, and more (best practices and common errors)

Analyze your site’s speed and make it faster.

It usually takes a long time for the DOM ready event to fire. During this time, many parts of a webpage are inactive as they wait for Javascript to kick in and initialize them. This delay is significant and makes a rich web application become available slower. Creates a bad user experience, doesn't adhere to any design pattern and is, really, not needed...

Given the potential limitations, let’s work on a solution that can handle all my concerns: a. works without JavaScript (i.e., lazy loading is an enhancement) b. vanilla js – no dependencies on jquery or angularjs c. works with broken JavaScript (i.e., the browser supports JavaScript, but there’s a js error somewhere which causes your script to break; might not even be your fault!)

A one-page questionnaire to help your team establish effective frontend guidelines, so that you can write consistent & cohesive code together.

This book is required reading for anyone who cares about web performance; it's already established as the go-to reference on the topic. —Mark Nottingham (IETF HTTPBis Chair)

While this article is about optimizations in AMP, it might also be useful as a kind of todo list for optimizing a non-AMP website.