Supermassive black holes preserve information on the growth of the host galaxy and its dynamic evolution. Thus, constraining their parameters is crucial to shed light on their formation and evolution. In recent years, X-ray astronomy has undergone a renaissance, with several instruments that perform large observational campaigns and cover an extremely wide range of energy timescales to study Active Galactic Nuclei (AGN). The X-ray radiation produced by the closest accreting matter to the black hole shows distortions due to the strong relativistic effects. Proper modeling of these features constrains the system geometry and the interplay between the corona and the accretion disk. I will review the recent results of X-ray spectral timing analyses with an emphasis on the interpretation of the observations.