How to check WebAssembly support before an audit

An accessibility tool or web app may rely on WebAssembly to run code in your browser. If it does not load, you need to know whether the browser lacks a required feature or something else is blocking the app.

Use the Browser Info tool to check the browser's reported support for WebAssembly before the audit. A supported result is a useful starting point, but it does not confirm that a particular app is accessible or that assistive technology works with it.

Check WebAssembly support

1. Open Browser Info in the same browser and profile you plan to use for the audit.
2. Review the supported features information and look for WebAssembly. If it is listed, note whether the browser reports it as supported.
3. Record the browser name, version, and engine shown in the report. These details help you repeat the check or describe the setup to your audit team.
4. Open the app or audit page in a separate tab and see whether it loads and runs the feature you need. Use the same browser profile and network you plan to use during the audit.

Testing in the same setup matters. A different browser, private window, extension, or managed work profile can change what a page is allowed to do. Do not assume that a result from one browser applies to another.

What the result means

WebAssembly is reported as supported

The browser reports that it can run WebAssembly. If the app still fails, the cause may be a separate requirement, a browser setting, an extension, a network restriction, or an app error. Continue with the checks below rather than treating the support result as proof that the app itself works.

WebAssembly is reported as unavailable

The browser or its current configuration does not report support. Check whether the browser is outdated, restricted by an organization, or running in an unusual environment such as an embedded browser. Try an up-to-date browser that your audit team supports, then check again in that browser.

You cannot find a WebAssembly entry

An absent entry is not the same as a confirmed failure. The browser or reporting context may expose limited feature details. Check the browser version and test the app directly. If the app gives an error, save the wording and include the browser details in your audit notes.

The feature is supported but the app does not work

WebAssembly support only confirms one browser capability. An app may also need JavaScript, network access, a compatible browser version, or a separate browser feature. The app may have a bug, too. Ask the app owner which browser versions and requirements the audit setup supports.

How to fix a missing or blocked feature

1. Reload the page and restart the browser. A temporary loading failure can make an app appear unavailable. Close the app tab, reopen it, and check the feature again.
2. Update the browser. Use the browser's About or update option, then close and reopen it. If the whole computer needs updates, on Windows 11 open Settings › Windows Update. On a Mac, open System Settings › General › Software Update.
3. Check whether JavaScript is enabled. WebAssembly is commonly used by web apps alongside JavaScript. In your browser settings, search for JavaScript and make sure it is allowed for the audit site. The exact setting location depends on the browser.
4. Test without extensions that filter or modify pages. Temporarily turn off content blockers, script controls, or privacy extensions for the site, then reload it. Restore your usual settings after the check. If you use a work profile, do not bypass your organization's security rules.
5. Check for managed browser restrictions. A school or workplace may control browser features through policies. If the option is locked or the feature remains unavailable, ask the administrator whether the audit site and its required browser features are permitted.
6. Compare with another supported browser. Check WebAssembly in the alternate browser and test the app there. If it works only in one browser, report the difference rather than changing several settings at once.

WebAssembly support is not an accessibility result

WebAssembly describes a way for a browser to run compiled code. It does not tell you whether an app has meaningful labels, visible keyboard focus, a sensible reading order, or controls that work with a screen reader. Those need to be tested directly in the app with the assistive technology and browser combination your audit covers.

Keep the checks separate in your notes: record whether the browser reports WebAssembly support, whether the app loads, and what happened during keyboard and assistive technology testing. This makes it easier to distinguish a browser setup problem from an accessibility barrier in the app.

Browser Info runs in your browser, and the result describes the browser on the device you are using.