There is a category of product that promises to make any website accessible by adding one line of JavaScript. Disabled users have been fairly consistent about these for years: they get in the way, they fight the assistive technology people already use, and they fix almost nothing that matters.
What actually matters
- Real headings in order. A screen reader user navigates by heading the way a sighted reader skims, and an h3 used because it looked the right size breaks that.
- Keyboard paths that work. Every interactive thing reachable by Tab, in a sensible order, with a focus ring you can actually see.
- Contrast measured at the size type is set. A grey that passes at 24px often fails at 13px, which is where most body copy lives.
- Labels on form fields. Placeholder text is not a label; it disappears the moment somebody starts typing.
- Alt text that says what the image is for, and empty alt on decoration so it is skipped rather than announced.
None of this costs anything at build time
Every item on that list is free if it is done while the page is being built, and expensive if it is retrofitted, because retrofitting means rewriting the markup. It is the clearest example we know of a quality decision that is only cheap when it is early.
Test it with the mouse unplugged. Ten minutes of tabbing through your own site finds more than any automated scan.
The commercial argument
About one in six people has a disability of some kind, and a far larger group benefits from the same work: anybody on a phone in bright sunlight is a contrast user, and anybody with a trackpad that has just died is a keyboard user. Building for the edge improves the middle.