A CAPTCHA (Completely Automated Public Turing test to tell Computers and Humans Apart) is used, but poses challenges for assistive technology users. If users are asked to enter text displayed in an image, or text heard in an audio file, doing so with assistive technology is more difficult.
- Alt text in images can not be read by bots.
- Audio does not interrupt and announce over screen readers.
- Methods to bypass CAPTCHAs create increasing distortion of visible images.
Ideally, avoiding CAPTCHA use will be the most accessible for a wide range of users, supporting keyboard-only and screen reader interactions.
Consider using an alternative to CAPTCHAs like a human logic test question, such as:
- Is fire hot or cold?
- Is grass green or blue?
Using a confirmation page as a second step verification will stop most spam bots.
Multi-factor authentication, such as a text message or email confirmation can also validate identity.