I created a web app for doing personal accounting with GnuCash files [1]. The mobile app for GnuCash was abandoned around 2018 from what I can tell, and it never had synchronization, so you couldn't easily use it on both mobile and desktop at the same time.
I'm one of only two users as far as I know. It's in a public repository, but I doubt anyone has used it. Personally, I use it nearly every day, and it has enough features that I rarely have to use GnuCash anymore.
The app isn't the most beautiful thing in the world, but it works just well enough to be usable.
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