The Localhost Holder Extension is a free Chrome add-on developed by cti-tl. It aims to improve the efficiency of web service development in a local environment by facilitating device testing.

It's important to note that if the redirect destination is set to "localhost" in SaaS applications, there may be cases where the extension doesn't function properly. However, it is primarily designed to make it easy to check layout issues without committing changes.

The Localhost Holder Extension provides several useful features, including the ability to register necessary hostnames for accessing local servers, the option to save frequently used port numbers, opening registered local servers in separate tabs, sharing settings via QR codes, and displaying QR codes with URLs (including page hierarchy) for locally running sites when the extension's popup is opened.

Please keep in mind that the extension cannot automatically retrieve hostnames and the input information is stored locally, except when accessed through QR codes on mobile devices.

Your feedback and opinions on the Localhost Holder Extension are greatly appreciated!