We present a detailed next-to-leading order (NLO) leading twist QCD analysis of deeply virtual Compton scattering (DVCS) observables, for several different input scenarios, in the MS scheme. We discuss the size of the NLO effects and the behavior of the observables in skewedness ζ, momentum transfer, t, and photon virtuality, q 2 = −Q 2 . We present results on the amplitude level for unpolarized and longitudinally polarized lepton probes, and unpolarized and longitudinally polarized proton targets. We make predictions for various asymmetries and for the DVCS cross section and compare with the available data.