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Articles by Ilya Grigorik

Ilya is a Developer Advocate and Web Perf Guru

Speed is now a landing page factor for Google Search and Ads

Speed is now a landing page factor for Google Search and Ads.

Chrome User Experience Report: expanding to top 1 Million+ origins

Today, we’re announcing a new Chrome User Experience Report with expanded coverage of over 1 million top origins on the web.

Introduction to HTTP/2

HTTP/2 (or h2) is a binary protocol that brings push, multiplexing streams and frame control to the web.

Delivering Fast and Light Applications with Save-Data

The Save-Data client hint request header available in Chrome, Opera, and Yandex browsers enables developers to deliver fast and light applications to users who have opted-in to 'data saving' mode in the browser.

Automating Resource Selection with Client Hints

Image optimization is hard and automation is the key to success.

Constructing the Object Model

Learn how the browser constructs the DOM and CSSOM trees.

Analyzing Critical Rendering Path Performance

Learn to identify and resolve critical rendering path performance bottlenecks.

Critical Rendering Path

Optimizing the critical rendering path refers to prioritizing the display of content that relates to the current user action.

Eliminating Unnecessary Downloads

You should audit your resources periodically to ensure that each resource is helping deliver a better user experience.

Measuring the Critical Rendering Path

Learn to measure the critical rendering path.

Optimizing Content Efficiency

The amount of data downloaded by apps continues to increase over time. To deliver great performance you must optimize data delivery as much as possible.

Optimizing Encoding and Transfer Size of Text-Based Assets

Next to eliminating unnecessary resource downloads, the best thing we can do to improve page-load speed is to minimize the overall download size by optimizing and compressing the remaining resources.

Optimizing the Critical Rendering Path

Learn the key factors in optimizing the critical rendering path.

PageSpeed Rules and Recommendations

This guide examines PageSpeed Insights rules in context: what to pay attention to when optimizing the critical rendering path, and why.

Render Blocking CSS

By default CSS is treated as a render blocking resource. Learn how to prevent it from blocking rendering.

Render-tree Construction, Layout, and Paint


Adding Interactivity with JavaScript

JavaScript allows us to modify just about every aspect of the page: content, styling, and its response to user interaction. However, JavaScript can also block DOM construction and delay when the page is rendered. To deliver optimal performance, make your JavaScript async and eliminate any unnecessary JavaScript from the critical rendering path.