YNAB to GnuCash Migration Tool
YNAB offers a CSV export of fall your data. This is an attempt to import that easily into GNUCash 5.8 using the python-bindings module.
It assumes the YNAB file has these columns:
"Account","Flag","Date","Payee","Category Group/Category","Category Group","Category","Memo","Outflow","Inflow","Cleared"