Hi I worked for an american company in europe last year,I myself am an irish citizen,I was paid per diem for the duration of the job,the irish tax system is similar that the per diem is not taxable ,can anyone confirm that the us system is the same,but because I worked for an american company I require confirmation from an american source.

If you are not a U.S. citizen or resident and you were not present in U.S. to work, your income from U.S. source is not taxable in U.S.