  The extraction of the parameters of perturbative QCD is one of the main tasks
for the HERA experiments. Studies on the structure of the hadronic final states
with jet algorithms give a direct handle on the parton density functions and
the strong coupling strength over a wide kinematic range. In this article, new
results of the H1 and ZEUS collaborations for the strong coupling and the gluon
density in the proton are presented.
