Can I use GnuCash with multiple users? Maybe via the SQL backend?
Especially since the SQL backend doesn’t support the business features, which is usually the driving desire for multi-user support, the only recommended multi-user setup right now is through a shared file. Note that this will enforce serialized, exclusive access to the data file and editing; there is no real support for simultaneous editing. File-locking is employed on this file, so it should be NFS-safe. SMB-safe locking is unknown.