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The WCAG 2.0 requirements and techniques regarding CAPTCHA include:

I evaluate the Google reCAPTCHA v2 with these two demo:

It seems that reCAPTCHA v2 has the provided the describe text (in aria-live="polite" div), and the alternative accessibility solution for screen readers, which can fulfil the above requirement.

And I learned from this answer that automated accessibility tools, e.g. the WAVE tool, may return specific false positive. Beyond that the reCAPTCHA seems fine on my scans.

So, are there any violations? Can we say reCAPTCHA v2 is currently conforming to WCAG 2.0 AA?

yhd.leung
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1 Answers1

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Conforming to WCAG

Yes, but only because WCAG has added exceptions for the inherent accessibility problems with CAPTCHA. Conformance is not the same as actually working for people with disabilities

It fails at the first hurdle as I can't find a text alternative which is an A level requirement and the first WCAG rule.

Now while that rule does provide for CAPTCHA (so you get a technical pass) it certainly does not fit the spirit of this rule and has always been a point of contention on WCAG.

Providing an audio alternative doesn't work as some people are deaf and blind, which is why a text alternative is a must (a programatically determinable description etc.)

Usable / a good experience / accessible, absolutely not!

  • If you have poor vision there is no way you can differentiate the images.
  • If you have a cognitive disability you may not be able to associate the images correctly with the question being asked.
  • Using it with a screen reader (as a blind user) is horrendous as you have to use the audio captcha.
  • The audio captcha is useless if you also have a hearing impairment (it is hard to use even if you don't).
  • Using it with a braille screen (if you are blind and deaf for example) is impossible.

I could go on, but you get the idea. Especially that last point. Yes Google provides alternatives to "tick the boxes" but neither option is useful for someone who is blind and deaf.

Is it effective at blocking spam?

Not really, you can buy 1,000 captcha solves for $5!.

All you are actually doing is helping Google perfect self driving cars image recognition when you implement a Captcha (why do you think they show you pictures of buses) and annoy your visitors.

In the mean time you are

  • introducing friction for users who want to fill out your form (and depending on usage could result in a lower conversion rate),
  • making the site hard or impossible to use for disabled users
  • probably making your site slower (depending on implementation) as the Captcha library is bloated, hurting your Core Web Vitals.

Avoid and do not use!

GrahamTheDev
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  • Thanks for the detailed answer and practical advice. W3C has also covered the inaccessibility of reCAPTCHA v2 and other approaches in https://www.w3.org/TR/turingtest/. – yhd.leung Dec 03 '21 at 03:27
  • Yeah that article is linked from within the text alternatives guidance I linked so I didn't think to link it separately. I perhaps should have done as it is a useful resource on its own! Glad the answer was useful and good luck in the project(s)! – GrahamTheDev Dec 03 '21 at 03:30