Testing Accessibility with Accessibility Insights

Posted by Anna Maier on December 9, 2019

There are many tools out there that help you check if your website or webapp is accessible. Most of them do an automatic check based on some accessibility guidelines. Some also provide functionality to do checks yourself, for example, to check the color contrast. The open source tool Accessibility Insights takes a different approach: on top of the usual automated checks there is a set of guided manual checks. This makes it a great tool to learn about accessibility testing and programming.


Accessibility Insights can be used as Chrome and Edge plugin (for the Edge insiders channel). I use it with Chrome. To start testing a page, you just need to click on the icon of the plugin. There are several options: FastPass, Assessment and Ad hoc tools.

FastPass consists of two tests (one automatic, one manual) for quickly checking the most relevant accessibility pitfalls. Assessment extends on that with a lot more manual tests to execute. Ad hoc tools provides some useful tools for quick accessibility checks.

Guided checks

The most interesting part is the Assessment part. It consists of 24 tests. The first test runs automatically, but all the other tests require manual work. In the manual part, the user is guided through the steps and provided with information and helper tools. The overall goal is to ensure compliance with the Web Content Accessibility Guidelines(WCAG), 2.1. Full compliance with WCAG can really only be ensured with manual testing.

There are different helper tools used throughout the testing process. The second test, for example, consists of six checks for keyboard navigation. It is supported by a tool that highlights the tab stops reached in a page.

A web page with highlighted tab stops
The tab highlighter in action

Other tests have a highlighter tool for different parts of the page. For some tests, Accessibility Insights scans the page and creates a checklist of the parts of the page that are relevant for the test. You can pass or fail each item on the checklist individually. Some tests also refer to tools that are not built by Accessibility Insights, like the Chrome Dev tools, Browser plugins, bookmarklets or even Windows settings.

For every test, you click pass or fail; and for most tests, you can also add a comment about the failure. Accessibility Insights keeps track of the progress and restores the session when the browser was closed during the test.

When done testing, you can export the results to an HTML report. There is also the possibility to integrate with Github or Azure Boards.

Report generated by Accessibility Insights
Report of a complete accessibility test

Learning about Accessibility

Accessibility Insights is a good tool to learn about accessibility, because every step is guided. Also, every test has a detailed explanation not only on how to test, but also why the test is needed. Additionally, there is information about how to fix the problems, which is especially useful for developers.

All this information is not only coming from Accessibility Insights itself, but also from external sources, like the site “Understanding WCAG 2.1” or the “WAI-ARIA Authoring Practices” on w3.org. The latter one explains how to build complex controls, like a menu or a tab control, in compliance with WCAG. This is also an interesting resource for developers experienced with accessibility.


I use Accessibility Insights a lot now, and find it a very useful tool. If I don’t do a thorough analysis, but just a quick check, I still go over the list of manual tests and pick out what applies to the current check. Also, there is a wealth of information in the tool which is arranged in an easy-to-digest way.

Still, some more features would be nice, like making comments possible everywhere, or exporting to some other format. But the activity on github is quite high, so new features might be added.

The only real big downside for me is that it turned out to be a bit buggy in Chrome. The highlighting and automatic element recognition broke regularly when using the recommended external tools. To prevent this, my current way of working is to run the external tools in a second tab. The behaviour might be better in Edge.

Some developers might consider it a downside that the tool is, although targeted for multi-platforms, better usable by Windows users. Some tests require Edge or changes in Windows settings.

Overall, I see Accessibility Insights as a good tool for accessibility testing and for expanding knowledge on accessibility.


Accessibility Insights provides a high contrast mode, which is probably intended for users with a visual impairment. But it is also really nice for developers that prefer to use the dark mode on their devices.

Accessibility Insights interface in high contrast mode
Accessibility Insights high contrast mode

About the author: Anna Maier

Software Developer at TOPdesk with a passion for good structured code, pragmatic solutions and learning.

More Posts