So reCAPTCHA has one of those challenges where you have to click images and new ones fade in to replace them. Why do the images fade out/in so slowly at times? At times it's almost instant, sometimes a bit sluggish and sometimes excruciatingly slow.

I often run into reCAPTCHAs where it takes full 5 seconds for the new image to fully fade in after clicking the previous one.

This combined with how unreliable the whole system is can sometimes cause it to take like minutes to get past them.

Why is it so slow? Is it intended behavior or is it some sort of bug?

I don't think it's a browser issue, but I mainly use Firefox if that matters. Though I seem to remember running into the same problem on Chrome as well.

I am using a VPN, which I'm assuming is the main reason I get reCAPTCHAs so often in the first place.

  • 3
    I get this same behavior you describe when using a VPN. The images are also more grainy and noisy, and I often have to go through multiple image sets. I've always assumed that VPNs are high-risk for bot traffic and that this was intentional behavior to thwart them, but I don't know if that is in fact true.
    – wysiwyg
    Jul 9, 2018 at 23:00

1 Answer 1


Wysiwyg is mostly correct. Captcha Type (I'm not a robot vs solving Captchas) and fading speed depends on Google and how your score for Human vs Bot is. Your score ranges from 0.0 (a bot) to 1.0 (definitely human). In the case Google is confident that you are human, then a click to I'm not a robot is enough. The worse the score is, the more and more and slower fading captchas you will get.

If you are using a shared IP address on a VPN, this means that you are not the only person using that IP address and that other people are using it as well.

What Google sees is a lot of searches that originate from the same computer which is something that is commonly done by bots and spammers. Because of this, Google requests that you verify that you are a human by requesting that you complete a Captcha occasionally. This will prove to Google that you are not a computer program that is making fake searches.

So it's not necessarily the fact that you're using a VPN. You just don't have full control of your score if you're using an IP that is shared. It's probably likely that bots are also using that same VPN or IP and driving down the score from time to time.

  • This is interesting.  Do you have a reference for it?  And, if the great and almighty Google believes that you are definitely human, why does it even display the “I’m a human” checkbox at all? Nov 11, 2018 at 22:21
  • 1
    @Scott I'd have to do some searching again. I found the fading speed info on some developer forum. I got the scoring rating from the reCAPTCHA documentation. I doubt someone ever gets an exact 1.0 score, but they still ask those with a good human rating score because they use the data to train AI.
    – DrZoo
    Nov 11, 2018 at 22:57
  • 1
    It's kind of outrageous. The Captchas fading in and out will drive a human crazy while the bot doesn't care. If they just want some arbitrary timeout to slow the bot down, just tell me to come back in 30 seconds, rather than force me to watch Captchas.
    – Tahlor
    Jul 31, 2021 at 5:00

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .