NLO calculations at small x

We discuss recent progress in next-to-leading order calculations for dilute-dense-processes in the small-x gluon saturation regime, especially for Deep Inelastic Scattering observables. A systematical formalism for such observables is provided by a combination of light cone perturbation theory for the dilute probe, combined with a Color Glass Condensate picture for eikonal scattering off the dense gluonic target. In particular we focus here on the recent calculation of the diffractive DIS structure function, which is expected to be more sensitive to gluon saturation than inclusive DIS observables.