A non-logged in user could have limited permissions to limit security risks. I think this is a preferred workflow actually, without evenn considering security concerns, as I wouldn't want to bog down my clients with lots of extra UI, and don't need them to make any other edits to a PDF. I just want to be able to send them a PDF for review and the only functionality they need is to be able to add inline comments to leave me feedback. I understand logging in isn't so hard, but still, it's an extra step, an extra account, plus email verification is always annoying lol. I just want it to be as easy as possible for them to look at a design and leave feedback. Oh, and it should definitely work on mobile :) I've found multiple almost-solutions that just don't even work on a phone without downloading an app (again, another extra step they shouldn't have to bother with) and there are so many folks that don't even own a desktop computer or laptop anymore. Honestly, the only solution for my use case I've found so far is DocuSign, which I already use for signature collecting. I actually can't believe they have an unauthenticated commenting feature built-in, after I spent days looking at other software without checking something I already use lol. Even so, I would still consider switching to Lumin for both PDF sharing and signatures if this unauthenticated commenting feature were ever added, as the price would end up being a little lower than DocuSign and your UI looks nicer :)