A CartoDB Platform app can be created with multiple layers, which are actually datasets stored in tables within the PostgreSQL/PostGIS database, allowing for a large number of layers to be supported. However, visualizations made through the CartoDB Editor have a limit of 4-6 sublayers due to performance constraints. To overcome this limitation, custom apps can be built using the CartoDB APIs and platform, providing full control over visualization choices and user experience. A template for creating multi-layer geoportal sites is available, which allows users to easily create their own app with a scrollable list of layers and toggle them on and off independently. The app uses the SQL API to retrieve layer metadata and visualize multiple datasets simultaneously.