Automated vs. manual accessibility testing: what each can prove

Automated testing

Strengths: fast, repeatable, cheap to run daily, perfect for catching regressions and for large page sets.

Limits: many WCAG success criteria require human judgement. A tool can see that an image has an alt attribute; it cannot say whether "IMG_2034" is a useful description of a product.

Manual testing

Strengths: judges meaning, context and real assistive-technology behaviour.

Limits: expensive, point-in-time, and outdated after the next release.

The combination that works

1. Manual audit to establish the baseline and fix structural problems.
2. Automated monitoring to keep those fixes in place and catch new problems early.
3. Periodic manual re-checks on the journeys that matter most.

This is why automated monitoring products — including ours — never state that a site is "compliant". They measure and track what can be measured.