The concept of the Virtual DOM technology in the library for creating web user interfaces React.js is considered. A comparative analysis of approaches to the construction of modern user interfaces is carried out. The technological implementation of the internal mechanisms and algorithms of the Virtual DOM concept in React.js is considered. Describes current trends in the development of web applications.

Keywords: data processing, data visualization, web applications, user interfaces, algorithms, software development, data updating, client-server applications, web development trends