Explore the world of web JavaScript mapping libraries with a focus on how developers can leverage tools such as Leaflet, MapLibre GL JS, and OpenLayers. This presentation examines the unique functionalities of these popular libraries, providing insights into how they can be effectively utilized in diverse web development projects. A comprehensive understanding of essential geospatial data concepts will be provided, along with best practices for creating effective web-based mapping solutions. Emphasis will be placed on the importance of data visualization and cartographic design, highlighting how these elements enhance the visual appeal and clarity of maps. Geared towards developers new to GIS and those seeking to enhance their existing mapping skills, the presentation offers an in-depth exploration of the latest trends and capabilities in open source web mapping technologies.