@oblomov @masukomi @tunafishtiger
This is an area where there are best practice standards to follow, and there are a variety of tools for both building and checking sites against those standards.
E.g.,
https://www.ada.gov/resources/web-guidance/
https://www.w3.org/WAI/standards-guidelines/wcag/
You can try out some of these tools for automatically checking the accessibility of your websites. Some of these specifically check against specific standards, others don't. Some are free, others paid.