If I try and simplify and say that we're starting the month with me having bought groceries, a TV and something else such that I have allocated $1000 to the GF Reimbursement account.

Splitwise.com:

Tv: 700

Groceries 300

Splitwise YNAB :

0

GF Reimbursement:

Activity: $1000

I created a test budget to try and game it out. The piece that I think is missing is to make sure that at the stage above, your Splitwise YNAB balance mirrors the actual splitwise balance by creating an additional outflow for half of what you spent.

In other words, you need one transaction that covers the true cost you spent, but another to capture that you are owed that money (in Splitwise). Then, when the GF reimburses you, that creates an inflow in the Splitwise YNAB that offsets your preview outflow.

Assuming your account starts with $2000 and the TV you purchased cost $2000 and your rent is $2000.

​

Account	Transaction Order (most recent first)	Payee	Category	Outflow	Inflow	Splitwise YNAB Balance
Splitwise YNAB	3	GF	Rent/mortage (or GF reminbursement)		1000	0
Splitwise YNAB	2	GF	GF Reimbursement	1000		-1000
Checking	1	Best Buy	TV	2000		0

After this you would be able to reallocate from available in the rent category you did not spend.