During the second-most-recent English Google SEO Office Hours (this one from September 24, 2021), John Mueller, who’s a Search Advocate at Google, replied to a question.
The question–rewritten for clarity–was:
“I wanted to know whether the indexing or crawling is impacted if there are captures presented to avoid scraping. My website has a strict captcha policy on directory pages.
“The whole purpose for these pages is to make sure that the pages are crawled and indexed. However, does the captcha slow the process down?”
John’s response was:
“So, Googlebot doesn’t fill out any captchas. Even if there are Google-based captchas, we don’t fill them out.”
With Regards to Googlebot, Does Your Captcha Need to Be Completed Before Content Is Visible?
“So that’s something where if the captcha needs to be completed in order for the content to be visible, then we would not have access to the content.
“If, on the other hand, if the content is available there without essentially needing to do anything, and the captcha is just shown on top, then usually, that would be fine.”
A Suggestion to Use The Inspect Tool
“Now, what I would do to test is use, in Search Console, the Inspect URL tool and fetch those pages and see what comes back: on the one hand the visible page to make sure that matches the visible content, and the HTML that is rendered there to make sure that that includes the content that you want to have indexed.”
You May Need Your Webmaster to Help With This
“So that’s kind of the approach I would take there, from a policy point of view we’re okay with situations where you serve us the full content and you require a captcha on the user side so if you need to do that slightly differently for Googlebot or maybe other search engines than you would for the average user, from our point of view, that’s fine.”
So, you can have captcha without blocking or preventing Googlebot from seeing your content. But you have to make sure that, from a coding perspective, this is done properly on your pages. Captcha should be a barrier for the user, not for Googlebot, and there are ways to ensure this.