Development of tool for visualizing open data about Italian public trains performance This thesis presents the design and implementation of a web application for railway performance analysis, developed as an extension of an existing open data project. The base Railway OpenData repository already provided data scraping, extraction, and analysis capabilities through command-line tools. The main contribution of this work is the development of a complete web platform that makes those data and analyses accessible to non-technical users through interactive visualizations and guided filtering. The implemented system includes a FastAPI backend, a React single-page frontend, dataset upload and archival workflows, monthly precomputed analytics, and custom range analysis.