We have been cooperating closely with Google and others since 2015 to ensure that the use of Cookiebot does not negatively affect your website's ranking and the indexing of its content or the website's performance. This was an important requirement for Google prior to them officially listing Cookiebot on www.cookiechoices.org.
- Any search engine crawler will access your website simulating a "full consent" (in effect, the cookie consent banner will not be visible to the crawler). This way the crawler will have access to all content on the website (and not be excluded from certain parts of your website that may not be visible to users who have not accepted certain categories of cookies).
- The cookie texts from the cookie consent banner are not indexed by the crawler and will therefore not affect the indexation of your website.
- The cookie consent banner is only shown to a special Adsense version of the Google crawler, which checks the ad partners’ cookie compliance.
- Cookiebot has minimal impact on the website's performance because the script is delivered in less than 100ms (on average). In automatic cookie blocking mode the script is loaded synchronously in order to apply control over all other scripts loading. In in manual mode however, it can be loaded asynchronously - meaning the rest of the website is not waiting for the Cookiebot script to be loaded, further improving performance.*
In other words, the search engine crawler will not "see" or be "blocked" by a Cookiebot consent banner or in any other way be affected by the use of Cookiebot. Do note however, that optimization tools may not always reflect this.
*In some cases, a minor delay in rendering is unavoidable when using automatic blocking, since our script evaluates all the elements that are added to the DOM. If you do find that the rendering delay is noticeable, then you should look into implementing manual blocking mode (or use Google Tag Manager or a combination of the two), as using Cookiebot in manual mode does not cause any rendering delays and gives you full control over exactly which elements are blocked.
Comments
16 comments
Hi, I have read your article but Cookiebot uc.js still shows up in pagespeed as a blocking resource. It takes up more than a second of time. I can imagine that a user will have this the first time but the actual pagespeed should be higher.
Pagespeed should not be able to detect cookiebot in order to verify actual pagespeed.
I completely agree, cookiebot whatever agreements you have with Google do not seem to be working in the real world. You've become 53% of the 3rd party problem on my site which itself accounts for 80% of the load speed reduction. This article is nonsense.

This is still an issue. Any update from CookieBot on this?
Is it possible to load /uc.js from a local ressource in order to speed it up?
I totally agree with WiseTribes comment.
Cookibot causes a rendering block of more than 2 seconds!
A total disappointment. ;(
I agree with WiseTribes and Borja. There is a significant rendering block originating from /uc.js.
Same Problem. /uc.js blocking for 1.9 seconds
Same here.
Some problem, the execution time varies from 0.3 to 0.9 seconds
Same here, 1.2s delay - not the 100ms promised in the article. Is there any update to this?
Dear Cookiebot support
I am still loving your solution in respect of GDPR.
However, I am facing the same performance issue here when running lighthouse in my Chrome browser, generating a report for mobile. It complains about render-blocking resources where uc.js stand out with 910 ms.
How can I improve this on my site https://www.beezital.fr/ (WordPress + Hummingbird)?
br, Fred
EDIT: some précision: uc.js is fine when running Lighthouse for desktop (I reach 100%) but shows bad performance when running Lighthouse for mobile.
Just to echo this one - I posted here 3 months ago. Any chance of a reply or are these support boards officially not supported any more? If so, could you please indicate that somewhere?
I'm experiencing the same thing. Would be very interesting with an update from the Cookiebot support here. As many others mention this affects mobile and results in a poor page speed result.
The blocking for me is approx. 1080ms
same problem here. Cookiebot is the last issue keeping our website to get a good Core Web Vital score, as everything else is optimized as good as possible to limitations by our javascript frameworks.
Is this problem in any way being adressed by Cookiebot? We are now planing / searching for alternative solutions and will probably remove Cookiebot from our projects…
cookiebots automatic blocking is great, but the time we spent on making everything else faster so cookiebot is not affecting CWV is now taking more time/effort then using some other cookie banner solutions which dont offer automatic blocking.
Same here, nearly one second of blocking script in this page https://www.itwreagents.com/rest-of-world/es/disolventes-agua
any solution?
Agusti
Hi all,
As stated in the article, the banner is not displayed to known search engines/crawlers, so any rendering delays will not affect your actual SEO, however optimization tools may not reflect this.
Sadly, a minor delay in rendering is unavoidable when using automatic blocking, since our script evaluates all the elements that are added to the DOM. If you do find that the rendering delay is noticeable, then you should look into implementing manual blocking mode (or use Google Tag Manager or a combination of the two), as using Cookiebot in manual mode does not cause any rendering delays and gives you full control over exactly which elements are blocked.
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