> We are developing an API to Firebird and in testing it, I have a sneaking
> suspicion that committing or rolling back transactions are not closing them
> out on the server. Or at least I need to test that this is the case.
>
> Is there an easy way to see any open transactions on a server at any time?

Call isc_database_info() with isc_info_active_transactions parameter.
(does not work for "read-only+read-committed" transactions)

Ivan