The role of functional and non-functional requirements in creating a quality software application is substantiated. Functional requirements describe the actions and tasks that the system must perform, while non-functional requirements concern the qualities and characteristics of the application, such as security, performance, usability, and reliability. Both types of requirements are integral parts of development, ensuring that the product meets user needs and business requirements. Attention is focused on the importance of correctly setting and balancing these requirements during the development process. Failure to accurately define or neglecting to define these requirements can lead to technical problems, increased costs for developing and maintaining the product, and deterioration in the quality of user experience. Methods for collecting and documenting requirements are substantiated, as well as key approaches such as Agile and Scrum, which help to effectively integrate both functional and non-functional requirements during the development process. Attention is focused on how functional and non-functional requirements interact with each other and affect the architecture, design, and testing of the application. The main results confirm that successful development of a high-quality application is impossible without taking into account both types of requirements at all stages of the life cycle.