In the following paper, I present through four practical examples how the development of mobile applications changed during the COVID-19 pandemic 2020 springtime. To what extent was the work of designers-developers determined by the quarantine, and by the possible time constraints? Which part of their work did they reduce most, and what could go on unchanged? The BPXV app was developed at the request of the 15th district of Budapest to help the district residents to shop and get their medicines during the confinement. A refreshing exception among the examples is the app created to replace Easter watering, Locsolkodj.hu. I also present two solutions suitable for contact tracking, the Virus Radar created in Macedonia, which became the official Hungarian contact tracking app, and the Austrian STOPP CORONA interface/platform? In order to find out the answers to the above questions, I conducted written and telephone interviews with the owners, designers, developers, or researchers of each site. Learning about design and development, I was interested in how the development of these apps, designed and developed at the time of the confinement, differed from the usual process -what the designers reduced, where were the "cuts" made. Based on the experience with the small sample, I found that the possibilities were typically limited in the user needs assessment and testing, but the Austrian example is a refreshing exception: it was tested by different methods, with the participation of the greatest number of real users (and not official employees or internal team members). It is a general experience that in the case of researched and introduced apps and websites designed and developed during a pandemic typically decreased the amount of classic user and usability tests. It is also characteristic that to the west of Hungary, the apps are tested by users, to the east by offices / officials / developers.