Website Critical CSS

Website Critical CSS to improve FCP score

Technical Name:
Sunflower IT
  • Odoo Version

Terms and Conditions 

Website Critical CSS

Beta License: AGPL-3 OCA/website Translate me on Weblate Try me on Runbot

This module can improve the Google PageSpeed score of individual website pages.

In particular, it improves the score for First Contentful Paint (FCP). It does so by allowing to configure a blob of 'Critical CSS' for each page, which is the only CSS that will be loaded before first paint. Any other CSS is delayed.

Table of contents


To use this module:

  • Go to Website -> Pages and select a page to optimize
  • Clear out any current contents of the 'Critical CSS' field
  • Find out the public facing URL of this page
  • Generate Critical CSS for this URL while selecting the right widths for Desktop and Mobile views
  • Paste the blob in the 'Critical CSS' field.

To generate critical CSS you have a couple of options:

  • Use a free online Critical CSS generator. At the time of writing there are: Sitelocity, Pegasaas,,, ...
  • Install the npm [critical]( package and generate it on your local.

To test improvement of FCP score, use for example Lighthouse, which is build into Chrome browser.

Known issues / Roadmap

  • Support automatic critical CSS generation when page layout is changed, when the critical tool is installed on server.
  • Investigate possible incompatibility with web_company_color Both are overriding the same function in ir.qweb

Bug Tracker

Bugs are tracked on GitHub Issues. In case of trouble, please check there if your issue has already been reported. If you spotted it first, help us smashing it by providing a detailed and welcomed feedback.

Do not contact contributors directly about support or help with technical issues.



  • Sunflower IT



This module is maintained by the OCA.

Odoo Community Association

OCA, or the Odoo Community Association, is a nonprofit organization whose mission is to support the collaborative development of Odoo features and promote its widespread use.

This module is part of the OCA/website project on GitHub.

You are welcome to contribute. To learn how please visit

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