About Accessibility Insights for Web
Accessibility Insights for Web is Microsoft's free tool for finding accessibility problems in web pages. It runs two main routines. FastPass is a quick check of common, high-impact issues, with a tab-stops review for keyboard problems such as traps and a wrong tab order. Assessment is the thorough one, testing against WCAG 2.1 Level AA with around 50 automated checks and roughly 20 guided manual tests.
It is built on axe-core, the same engine behind Deque's tools, and the whole project is MIT licensed on GitHub. The Chrome version runs on Manifest V3 and was updated in September 2026, and an Edge listing is published by Microsoft. Telemetry is opt-in: the documentation says anonymised usage and crash data are collected only with consent, and you can switch it off at any time.
The main limitation is browser coverage. It is available for Chrome and Edge, with no Firefox or Safari version, and note that a similarly named Firefox listing is not from Microsoft. Deque's axe DevTools is an alternative with a free version, but its Chrome rating is lower, at 3.2 out of 5. If you want a free, transparent accessibility checker you can use to learn as well as to test, this is the one to pick.
Pros and cons
- Free and open source under the MIT licence
- Quick FastPass check plus a guided WCAG 2.1 AA assessment
- Uses the axe-core engine
- Telemetry is opt-in
- No Firefox or Safari version
- Full assessment takes time, with about 20 manual tests
Permissions
It requests tabs, scripting, web navigation, storage and notifications permissions, plus active tab access, and asks for access to the sites you test as an optional permission.
