What Is the Critical Rendering Path (CRP)? Why Does it Matter?

May 2023

There are many different terms that tend to come to mind when thinking about website performance. Page-loading times and speed are a couple of metrics that are often focused on as a reflection of a site’s overall performance and usability. What many people don’t realize, however, is that these metrics are directly influenced by something known as the critical rendering path (CRP).

By honing your understanding of the CRP and why it matters, you can take the steps necessary to optimize your site’s performance.

What is the Critical Rendering Path?

Specifically, CRP refers to the exact sequence of steps that a browser follows to convert a site’s coding into actual pixels on the screen. And while there can be some variation from one browser to the next, the basic CRP is as follows:

  1. Document Object Model (DOM) – Coding is scanned and bytes are converted into characters. Tokens are identified and converted into nodes, then used to build a DOM tree.
  2. CSS Object Model (CSSOM) – The same process is followed, but with any CSS coding.
  3. The Render Tree – DOM and CSSOM are combined to create a final render tree.
  4. Layout – The browser determines each page element’s proper size and position.
  5. Paint – The browser “paints” the pixels onto the screen.

Why Does the Critical Rendering Path Matter?

Why is this series of events so important when it comes to page performance? Because (when properly optimized) CRP can prioritize the display and loading of page elements to enhance user experience. An optimized page can load seconds faster than a non-optimized page — and it’s no secret that seconds matter from a user experience standpoint. When your site is optimized, you’ll keep users engaged longer and reduce your bounce rate.

How to Optimize Critical Rendering Path

You can take a few proactive steps to optimize the CRP on your website, one being to simply compress your HTML and CSS coding as much as possible. This can speed up the object model steps in the CRP process, which are often the most time-consuming.

Suppose you’re well versed in coding; reviewing your code to ensure that no extra or needless rendering at the top level is necessary. From there, you can clean up your code and improve performance in the process.

Upgrade Your Hosting Today

In addition to optimizing your site’s CRP, you should also review your hosting plan if you’re looking to optimize your site’s speed and overall performance. Specifically, if you don’t already have a dedicated hosting plan for your site, now may be the time to make the upgrade.

At ReliableSite, we offer dedicated servers to suit your needs so that you can optimize your page-loading times and keep your site visitors happy. Contact us today to learn more about our hosting plans or for help choosing the hosting option best for you.