Accessibility Testing

Find WCAG violations automatically, and know what automation cannot catch.

8 specialist tools4 free or open source4 self-hostable

What this category is really about

Automated accessibility checks reliably detect somewhere around a third of WCAG issues — missing alt text, insufficient contrast, unlabelled form fields, broken heading order. That third is genuinely worth automating because it is cheap, deterministic and recurring.

The other two thirds — whether the focus order makes sense, whether an ARIA label describes what the control does, whether a screen-reader user can complete checkout — require a human, ideally one who uses assistive technology daily. Any vendor implying full coverage from a scanner is overselling.

In the EU, the European Accessibility Act obligations applied from June 2025, which moved this category from good practice to procurement requirement for a lot of teams.

What to evaluate

Rules engine

Most tools wrap axe-core. If so, you are choosing workflow and reporting, not detection quality.

Shift-left integration

Linter, browser extension, CI gate. Catching a contrast failure in review costs a minute; catching it in an audit costs a sprint.

Guided manual testing

The valuable premium feature: structured walkthroughs for what scanners cannot see.

Reporting format

VPAT/ACR output matters if you sell to government or enterprise procurement.

Common mistakes

Treating a zero-violation scan as a conformance claim.
Fixing contrast by lightening text until the scanner passes and the design stops working.
Adding ARIA to patch a problem that correct semantic HTML would have avoided.

8 tools built for this

Sorted by how widely adopted they are, not by preference. Tick the compare boxes to put two or more side by side.

Filter these

axe-core

The open-source accessibility rules engine almost every other tool is built on.

Open sourceSelf-host

Lighthouse

Google's built-in audit for performance, accessibility, SEO and best practices.

Open sourceSelf-host

axe DevTools

Deque's commercial layer over axe-core: guided manual testing and enterprise reporting.

from $40

Siteimprove

Enterprise accessibility, SEO and content-quality governance across whole websites.

Talk to sales

WAVE

Visual accessibility evaluation that shows problems in place on the page.

from $0.04

Level Access

Accessibility platform combined with expert audits and legal-risk support.

Talk to sales

Pa11y

Command-line accessibility testing for CI, with a dashboard for tracking over time.

Open sourceSelf-host

IBM Equal Access Toolkit

Free accessibility checker and rules engine from IBM, with a strong developer extension.

Open sourceSelf-host

Tools that also cover this

These are built primarily for something else but handle this category as part of a broader platform — often a way to consolidate two subscriptions into one.