CAPTCHA alternatives

If your web forms are getting spammed, and CAPTCHA isn’t a good solution, here are some possible alternatives.

The Akismet service has a good reputation, and is widely used by Wordpress amongst others. It could be another layer of protection against spam.

Jared Smith of WebAIM has compiled a series of server-side processing techniques that get rid of spam without the use of
CAPTCHA. Scripts are provided in PHP.

Spam-Free Accessible Forms

The scripts include:

  • Detect spam-like content within submitted form elements
  • Detect content within a hidden form element
  • Validate the submitted form values
  • Search for the same content in multiple form elements
  • Generate dynamic content to ensure the form is submitted within a
    specific time window or by the same user
  • Create a multi-stage form or form verification page
  • Ensure the form is posted from your server