Suggestions for multi-user / multi-device finance manager software?

[Christian Stimming]

Dear all,

here's a somewhat heretical question from me as a long-term gnucash  
user and developer: Gnucash no longer fulfils my requirements as a  
personal finance manager, and I was wondering whether anyone here has  
other suggestions I should try.

Here are my requirements: (1) I want to track my daily cash expenses  
of my spouse and me, using our mobile devices (two Android phones).  
(2) Additionally I want to keep track of our bank account by using the  
transaction download function of the German online banking protocol  
HBCI, so that every few days I can check the bank account balance and  
transactions. I used to do this on my desktop PC, but it doesn't  
really matter whether I do this on the desktop PC or on some mobile  
device. (3) Additionally every few weeks I want to check the cash  
flow, balances, and expense statement in detail to have an overview of  
where the money goes.

Unfortunately gnucash doesn't fit for tracking expenses on multiple  
mobile devices, let alone for checking the current balances from  
multiple devices. The gnucash data model is great, but our  
implementation of the "engine" code everywhere assumes that all data  
is held in the current device's memory. This is an obstacle against  
implementing a multi-user or multi-device editing possibility of the  
data. I tried our SQL database backend, so that the SQL database could  
be accessed remotely from multiple places. Alas, on start-up of  
gnucash, all data from the SQL database needs to be read into memory,  
effectively making it impossible to run gnucash from anywhere else  
except localhost of the SQL database host (otherwise it takes simply  
forever). My conclusion here is that unfortunately the existing  
implementation of gnucash's data access layer makes it impossible to  
run a multi-device / multi-user service on top of the data. Hence I  
will have to switch to some different software implementation.

I tried gnucash-on-android for quite some time, using this App as  
data-entering app and importing the data into desktop gnucash  
regularly. However, this extra step of importing a file into gnucash  
sucks. Theoretically, this might work if at least the  
gnucash-on-android app has the identical account frame so that the  
entered transactions can be imported without any extra double-checking  
on the gnucash side. But to my knowledge this is not implemented and I  
will always have to run the import-dialog on the gnucash side to  
ensure the correct other accounts are chosen, but this dialog sucks.

To summarize, my requirement #1 cannot be met by gnucash, even though  
the requirement #2 and #3 are still great in gnucash. What I would  
need for the multi-user / multi-device expense tracking is some sort  
of cloud service with access from multiple locations. I'm also willing  
to pay for this, but would also be interested to invest some work into  
Open Source solutions. Maybe there is some Open Source software for  
this, and the actual data hosting service is sold for some reasonable  
subscription fee. Ideas, anyone? Thanks a lot in advance.

Regards, Christian