Software development process is a process of dividing software development work into smaller, parallel, or sequential steps or sub-processes to improve design and/or product management. Software creation is complicated. Usually, it consists of a certain number of phases. Understanding the details of each phase is essential for the successful implementation of the software product and its support in the future. The textbook helps to form a theoretical and practical understanding of software development lifecycle. The peculiarities of unit testing of web projects developed on the ASP.NET platform using XUnit, Moq libraries are also analyzed using practical examples.