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Smart SEO Newsletter

Optimize critical rendering path

Published 8 months ago • 1 min read

Do you know what the Critical rendering path is?

It’s what your browser goes through in order to build a beautiful usable page from your source code.

It requires communication between the server and browser:

Steps to render a page in a browser (Critical rendering path)

  1. Begin constructing the DOM by parsing HTML incrementally
  2. Request CSS and JS files
  3. Parse CSS and construct CSSOM
  4. Execute JS, build a render tree
  5. Merge Document and CSS Object Models
  6. Run layout and paint

Optimizing critical rendering path

  • Let needed HTML load first
  • Eliminate render-blocking CSS (using media tags)
  • Minimize parser blocking JS:
    • Remove unneeded JS
    • Use async attribute
    • Use in-line JS if it’s needed just on a single page

Psst... Did you know that Tech SEO Pro has a dedicated module to advanced page speed optimization, including critical rendering path improvement?

After this module, you will:

  • Understand CVW and the 2 ways they are measured
  • Learn secrets about your Core Web Vitals scores
  • Get all tools you need to properly analyze page speed
  • Learn how to provide meaningful page speed recommendations
  • Understand the right way to approach CWV optimization efficiently
  • Get the ultimate scheme for page speed improvements that will save you time
  • Learn how browsers work and what you can do to optimize critical rendering path

​Check out other Tech SEO Pro modules and watch free previews>​

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Optimize critical rendering path

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Smart SEO Newsletter

by Kristina Azarenko. Tech SEO Pro

I'll help you trade an imposter syndrome for a technical SEO superpower. My mission is to break down and simplify complex technical SEO things so that you can understand and use them to advance your SEO career.

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