Online implementation of localStorage

I want to share with you how private mode Safari led to the development of a simple storage key-value on Node.js with backup, access to data from certain domains and password protection from writing and cleaning the repository.
Online implementation of localStorage
It all started with the fact that I was given the task to implement a test order in a web application that is built-in via iframe in one popular resource.
The problem was solved and worked as follows:
an unauthorized user clicks on the store (link "_blank");
In a new window, the test items are displayed, and in the iframe we redirect the user to the profile of ...