Inside the Web Browser’s Performance API

Building a beautiful, feature-rich website is easier than ever before. Not long ago, you’d have to fire up a text editor and hand-craft a lot of HTML, CSS, and JavaScript. Today, you can use WYSIWYG tools and third-party libraries that make development much simpler. The flip side of this is that it can be hard to see everything that’s going into your website — and the performance can suffer.

The good news is that modern web browsers expose lots of performance data that can help you understand how your web page performs. With the launch of Browser Insights today, we can analyze the performance from the perspective of the web browser and what the end user actually experiences. In this post, we’ll dive into how we think about performance and utilize the timing APIs in the web browser.

How web browsers measure performance

In the old days, the only way for a developer to profile performance was to intercept requests and measure the time from the beginning of the page load until the end of the load event.

Today, we can use Web APIs that are supported by modern browsers. This is part of the web standard called the Performance Continue reading