Google Drive and Dropbox have typescript SDKs that allow me to use them as file storage backends for e.g. an "offline only" app that does not have a backend. Google Drive is messy to use because you have to reauthenticate a lot. Dropbox is really good and has worked great for me for months now. But Proton Drive doesn't have an OAuth SDK so I can't use it because having a privacy-focused offline only app means users who care about privacy will use it, and if they have to enter their proton username and password they will probably not use that feature. OAuth however is a different story since YOU handle the credentials and just give back a token.