Abstract
The article examines Key Performance Indicators (KPIs) as a tool for assessing the quality and performance of web applications. A classification of KPIs is proposed based on technical, user-oriented, and business-related criteria. The paper analyzes current approaches to measuring each of these categories and provides examples of KPI implementation in various types of web systems. Special attention is given to the relationship between technical metrics and the quality of user perception. The findings may be useful for software engineers, analysts, and project managers in planning the development and optimization of web applications.