How to Use Browser Automation for Accessibility Testing

Automated accessibility testing runs a browser against your pages and flags problems such as missing image descriptions, low contrast and unlabeled form fields. It's fast and repeatable, and it catches regressions before users do. It can't replace human testing, but it makes human testing more productive.

Tools that automate checks

• axe-core: an open-source rules engine from Deque, used inside many other tools. It plugs into test frameworks such as Playwright, Cypress and Selenium.
• Pa11y: a command-line tool that tests pages or lists of pages and reports issues.
• Lighthouse: built into Chrome DevTools, with an accessibility score; Lighthouse CI runs it automatically on each change.
• Browser extensions: axe DevTools and WAVE run the same kinds of checks on the page you're viewing. See accessibility testing extensions.

A simple automated setup

1. List your most important pages and templates: home, product, article, form, checkout.
2. Write a test that opens each page in a headless browser and runs axe on it.
3. Fail the build on serious and critical issues.
4. Run tests on every code change, and on a schedule for content changes.
5. Test pages in different states: menus open, forms with errors, dialogs showing.

What automation catches well

• Images without alternative text.
• Color contrast failures.
• Form fields without labels.
• Missing page language and titles.
• Invalid ARIA attributes and duplicate IDs.

What it misses

• Whether alt text actually describes the image.
• Whether keyboard focus moves in a logical order.
• Whether content makes sense when read by a screen reader.
• Confusing wording, instructions or error messages.
• Problems with custom widgets that look fine to rules.

Automated tools find only part of real accessibility problems, so a clean report doesn't mean a page is accessible.

Manual checks to add

1. Keyboard only: tab through every page and complete key tasks. See keyboard-only navigation.
2. Screen reader: try NVDA on Windows or VoiceOver on Mac on your main tasks.
3. Zoom to 200% and check nothing overlaps or disappears.
4. Test with people with disabilities, the most valuable check of all.

Visual review across many pages

For a quick visual pass after a design change, AutoBrowser can play a folder of page bookmarks one after another in a single tab, so you can watch for broken layouts. It doesn't test accessibility itself; use the tools above for that. See WCAG 2.2.