it's not wrong, but kontera is the very specific act of assigning a transaction to the proper account, with none of the general meaning of classify. Kontera sort of implies the act and transaction, the "commit".

Yes, I probably explained it a little too simplistic. Describing it as the commit is quite accurate I think. In my program I came up with the verb "book" for this, as book a transaction, but I have no idea if it is correct in the English-speaking world.

I'm native English speaker, learned Swedish while living there for 7 years.

Yes, "book" is the right translation. Though "book" can mean many other things in English.

To book a transaction means "to enter the transaction in the bookkeeping system", hopefully in the right account.

maybe record? or enter? I'm not sure what I'd use and I'm a native english speaker : )

They are probably fine but in my ears they lack the precision that the Swedish word has.

It wouldn’t be the first time! I think the suggestion given below, “allocate”, is the best yet.

When I am communicating with accountants about this process the verb I use is “allocate”