The phone apps (iOS and Android) always work. On a computer, ToolBerry works in regular Chrome, Edge, Brave, Safari, and Firefox, and saves your data normally.
The one exception is private or incognito windows. In Safari and Firefox private windows the app won't load at all. In Chrome, Edge, and Brave incognito it runs, but everything is erased when you close the window. Either way, use a normal (non-private) tab, or the phone app, so your work is saved.