Diffuse X-ray emission from hot gas in planetary nebulae (PNe) was hinted by ROSAT and ASCA, but only the improved sensitivity and spatial resolution of XMM-Newton and Chandra have allowed detailed studies of the hot gas in PNe. These studies are helping us to better assess the effects of fast stellar winds and collimated outflows in the shaping and evolution of individual PNe, but a comprehensive picture is lacking, because the X-ray analysis of different PNe is not homogeneous and, therefore, cannot be intercompared. Furthermore, a significant number of X-ray observations of PNe that did not detect X-ray emission have not been reported. We have undertaken a systematic study of all XMM-Newton and Chandra observations of PNe benefiting from a homogeneous analysis using the most up-to-date versions of SAS and CIAO, respectively, and the recently released calibration files with greater accuracy for energies below 1.0 keV. We present reprocessed event files, derived data products (X-ray images and spectra), supporting observations at other wavelengths, and analysis results in a database, the XPN Database, that can be accessed at http://www.iaa.csic.es/xpn