Empirical data on the seismic behavior of masonry buildings are collected by technicians through rapid visual assessment procedures, i.e., by filling in forms that organize information in short answers or ticks. The resulting empirical database serves as a basis for prevention strategies, but the archiving and the post-processing of data are always a potential cause of losses and misinterpretations. New technologies are nowadays entering seismic risk analyses as a support to the usual visual approach. This paper proposes a new application for Android mobile devices that digitalizes an assessment form (MUSE-DV) able to collect damage and vulnerability data of masonry buildings in seismic areas, including information on strengthening interventions applied to buildings in the past. The client–server architecture of the app considers local devices communicating over the web with a central unit; data processing is split between them to reduce network and resource needs. This approach is convenient with thin devices, such as smartphones, and in post-disaster situations, when the mobile network may not be available. Data collected onsite can be stored in remote archives and therefore shared among technicians without affecting the integrity and consistency of the database. The whole dataset can be extracted and processed by a dedicated software for statistical and spatial analysis. The MUSE-DV procedure was validated in the area struck by the 2016 Central Italy earthquake and the app presented here was preliminarily tested onsite on the buildings of Castelsantangelo sul Nera (Macerata district); the results contributed to damage and vulnerability analyses by the means of thematic maps.