Despite the somewhat misleading headline, the Supreme Court didn't really say anything new here. They declined to hear Domino's appeal of the Ninth Circuit's (unanimous and clearly correctly decided) reversal of the District Court's absurd dismissal.

Domino's tried to claim that their due process rights were being violated since there is no federally-mandated standard for accessibility. But the ADA is clear: businesses have a legal requirement to ensure that disabled customers have "full and equal enjoyment" of their goods and services. Domino's made the tenuous argument that the lack of a specific standard meant that they didn't receive fair notice.

Robles, the plaintiff, argued that the appropriate standard to apply was WCAG 2.0. Instead of offering a different possible standard (which would have been a defensible legal rationale), Domino's position was basically, "fuck off".

It's really not hard to make your websites accessible at a basic level. Follow the standards. Make sure your content and markup are reasonably semantic. Use standard form components for data entry. Where more complex, visual-first designs are employed, make sure there are text-based fallbacks.

If you are a professional software developer, doing this is not just your legal responsibility, it's your moral responsibility.