INeedMana

I hope Logseq OG will be accepting PRs. I’d hate to go back to Obsidian

If they could be using web UI (I’m not sure how a client would work with auth like that) then it kind of depends on how much hassle they can live with and how secure you want to be

Simplest would be to use https://doc.traefik.io/traefik/reference/routing-configuration/http/middlewares/basicauth/
You set up username and password and share those with the user. But it can be brute-forced

Something more secure but also a bit more demanding would be some kind of email otp
https://docs.goauthentik.io/add-secure-apps/flows-stages/stages/authenticator_email/
Set up authentik to send time-limited link to their email that well let them through. But they would have to authenticate every time they access

AFAIK the apps are rather based on the APIs. And in general APIs usually don’t require a User-Agent header as they return only data, without the html

Do you know of an app that is setting user agent?

I guess, pick one that you like and check (check code or network traffic) if it’s setting user-agent header

What do you mean by “device or client details”? If you want to log in, it will have to send your credentials

As for fingerprinting, does any of the open source clients do that?