Development of the mobile application and optimization of the calculation method of the ordering cost of the stretch ceilings using NoSQL Database MongoDB

The article considers the issue of optimizing the method of calculating the cost of ordering stretch ceilings, which would take into account the curved shape of the ceiling, the presence of additional corners and additional elements, such as lighting points, air conditioning and ventilation systems, backlighting and various decorative finishes. Analysis of web and mobile applications showed the limitations of developments for calculating the area and cost of stretch ceilings. The authors have developed a mobile application for processing orders for stretch ceilings, which allows you to create drawings of any shape with the ability to indicate additional corners on the ceiling drawing, visualize the location of chandeliers, lamps, tracks, cornices and backlighting, automate calculations of the necessary materials for a specified area of ​​​​the stretch ceiling. The created software application also provides the ability to store customer profiles, as well as complete information about planned and credited orders and generate reports on the work performed. The paper conducted a comparative analysis of mobile application development tools and proved the advantages of the non-relational database MongoDB compared to the relational database MySQL when creating this application, for which ER diagrams were built for both options. The feasibility of choosing the Ionic Framework and the TypeScript programming language for developing the client part, as well as NodeJS and the JavaScript programming language for the server part, was substantiated. To assess the effectiveness of the developed mobile application, such indicators as the number of downloads, the number of registrations, user engagement, average session duration, customer retention rate, virality, customer churn rate, metrics for measuring monetization (ARPU and ARPA), the cost of attracting one user, customer lifetime value (LTV), the price of an effective installation, the return on advertising investments, etc. were analyzed. The Flurry platform was used to provide an assessment, which is used to collect and analyze mobile application statistics. The results of the analysis showed the demand for the developed application, namely the increase in the average session duration by two times in three months, while in order to increase the number of active users, it is necessary to pay attention to the issue of promoting this development