Interoperable Top Level Domain Name Parsing comes to IE

As part of our ongoing commitment to help build an interoperable Web that “just works,” we are changing the way Top Level Domains (TLD) names are parsed to use the Public Suffix List. This change can be previewed using Internet Explorer in the Windows 10 Technical Preview.

In the past, IE used a custom algorithm and kept a private list of domain name parsing exceptions. Owners of domain names that needed exception handling by our algorithm had to notify Microsoft that exception parsing was required.

Going forward, to increase interoperability we are switching our parsing to use the algorithms and domain list found at, which is a cross-vendor initiative also used by other browsers. Starting with the Windows 10 Technical Preview, IE will parse domain names in a more interoperable manner. After this change has been released in a product release you will no longer need to notify Microsoft of special domain names; we will automatically pick up and include the changes made at on a regular cadence. We are also evaluating bringing this change downlevel to accelerate the transition.

Join the Windows Insider Program to try the new top level domain name parsing in IE and let us know if you have feedback @IEDevChat or on Connect.

— David Walp, Senior Program Manager, Internet Explorer