W3C, the web standards organization, defines accessibility as:
Web accessibility means that websites, tools, and technologies are designed and developed so that people with disabilities can use them.
An ever-increasing number of organizations are creating accessible websites for ethical, legal, and even business reasons. It’s best to bake accessibility best practices in your developer culture so that a website or web app is accessible from the get-go. Often an existing website is refactored to make it or keep it accessible. Accessibility (a11y) testing is usually the starting point in such cases.
As per the stackoverflow podcast episode How we’re making Stack Overflow more accessible, automated a11y testing tools like aXe, Google Lighthouse, and Pa11y will cover only up to 57% of all accessibility issues. To spot the remaining 43% issues, manual testing is required.
Fun fact: In 2020, when Covid was unfolding, I led the team that made accessible the websites of Yas Island and its properties.