The "Mobil tEst" application on mobile phones was developed under the project management of the Grand Est Region with the financial support of the Banque des Territoires.The ArxIT company developed the application as part of a public contract awarded by the Grand Est Region. The objective of the "Mobil tEst" application is to improve information for mobile phone users on the quality of the services actually offered by the operators, in their places of life and activity as well as during their travel and encourage operators, within the framework of government measures, to improve the accessibility and quality of their mobile services in the territory. The use of the application is very simple and intuitive so that the maximum number of users can contribute to the identification of poorly covered areas of our territory. The measures taken by the users feed a regional database which does not include any personal information. They make it possible to produce coverage and quality of service maps that reflect the reality of the experience of users of mobile networks in the Grand Est region. They will complement the maps made available on the websites of operators and ARCEP (Regulatory Authority for Electronic Communications and Posts). The Grand Est Region and its partners will thus have new information to better identify areas that are still poorly covered. They will thus be able to guide and encourage operators to make new investments so that each inhabitant has access to an efficient and quality mobile network throughout the territory.The use of the "Mobil tEst" application requires the consumption of data from your mobile subscription, so you must ensure that you have a subscription with mobile data, especially in the context of the complete tests.