CAPTCHA: accessibility for developers [checklist]

  • Author: Access iQ ®
  • Date: 1 Feb 2013
  • Access: Free

Quick facts

Tips and tricks for making CAPTCHA accessible to as many people as possible, and alternatives to CAPTCHA.

  • Assess the security requirements and determine if an alternative to A CAPTCHA can be used, such as spam filters or heuristic checks.
  • Make CAPTCHA tests available in more than one modality e.g. as a visual test and an audio or textual test.
  • Ensure that all components within a CAPTCHA, such as buttons comply with all other accessibility requirements including keyboard accessibility and visible focus. Often a third-party CAPTCHA that claims to be accessible will only provide an audio alternative but not meet other accessibility requirements.
  • Ensure that the text alternative for CAPTCHA images identifies the type of task and what is required from the user to complete it. If there is an audio CAPTCHA as an alternative, the text alternative should describe this task.
  • Test with a range of people with different disabilities to ensure usability of the primary and alternative CAPTCHAs.


Media Access Australia, as a leader in accessibility, has a wealth of resources for organisations looking to make their workplaces, systems and processes more accessible for people with disabilities.

These include expert guides such as the Service Providers' Accessibility Guide and Sociability: social media for people with a disability. We also have a dedicated web accessibility hub, Access iQ and provide professional accessibility services and practical advice. For those seeking professional development in web accessibility, we have partnered with the University of South Australia on the Professional Certificate in Web Accessibility