Block the Serial API on specific sites

Define a list of sites, based on URL patterns, that can't ask the user to grant them access to a serial port.

If you don't configure this policy, the global default value from the 'DefaultSerialGuardSetting' (Control use of the Serial API) policy (if set) or the user's personal configuration is used for all sites.

For URL patterns that don't match this policy, the following order of precedence is used: The 'SerialAskForUrls' (Allow the Serial API on specific sites) policy (if there is a match), the 'DefaultSerialGuardSetting' policy (if set), or the user's personal settings.

The URL patterns in this policy can't conflict with those configured in the 'SerialAskForUrls' policy. You can't allow and block a URL.

For detailed information about valid URL patterns, see

Example value:

Supported on: Microsoft Edge version 86, Windows 7 or later

Block the Serial API on specific sites

Registry PathSoftware\Policies\Microsoft\Edge\SerialBlockedForUrls
Value Name{number}
Value TypeREG_SZ
Default Value


Administrative Templates (Computers)

Administrative Templates (Users)