The most frequent issues detected by axe-core (the engine also used by Chrome DevTools, Google Lighthouse, and Semnal) — with a concrete code example, not just theory.
The most common error found on the web. A screen reader can't "see" an image — without
an alt attribute, it just announces "image", with no context. For someone
navigating with a screen reader, a page full of "image, image, image" is unusable.
If the image is purely decorative (adds no information), use alt="" —
empty, but present — so the screen reader skips it, instead of reading out the filename letter by letter.
A placeholder is not a label. It disappears the moment the user starts typing, and some
screen readers don't announce it at all. Without a properly linked <label>,
someone navigating by keyboard or screen reader doesn't know what to enter in the field.
WCAG 2.1 AA requires a minimum of 4.5:1 for normal text and 3:1 for large text (18px+ bold, or 24px+ normal). Light gray text on a white background, trendy in a lot of "minimalist" design, often fails this test — and it's hard to read for anyone with reduced vision, not just people with a diagnosed visual disability.
"Click here" or "read more" say nothing if a screen reader reads them out of context, separate from the surrounding paragraph — and many users navigate exactly that way, listing every link on the page at once.
Without lang="en" on the <html> tag, a screen reader
doesn't know which pronunciation to use and may read the entire page with the wrong
accent — a page in one language read with another language's pronunciation is practically unintelligible.
These are just 6 of the dozens of WCAG 2.1 AA rules checked automatically.
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