The final paper is made of two parts, first part of the paper is a theoretical part, which describes the ETL process, that is the process of extract, transformation and loading data. The types of applications that enable the ETL process, commercial and open-source applications are described, as well as the advantages and disadvantages of these applications with their examples. A separate chapter describes databases, and concepts related to databases and the database management system. In order for the ETL process and infrastructure to be effective, care must be taken both to monitor the ETL system and to optimize the ETL process. Invalid data appears in the data warehouse at different scales of arrivals. Regardless of the frequency of occurrence, the information system architect must know how to detect and handle faulty data. Real-time ETL is also described, which refers to the processes of extracting, transforming and loading data from various sources into a centralized reporting and analysis repository. In the second, practical part of the paper, after the Python programming language is described, the ETL process is explained on a specific example, and the ETL application in the Python programming language is created. By transforming the display data from a human-redable format produces a file format that is suitable for storage in a relational database.