The Electronic Spatial and Urban Planning Support System (E-TÉR), developed by the Lechner Knowledge Center, is Hungary’s most advanced and integrated online platform for spatial and urban planning. Designed as part of the KÖFOP-1.0.0-VEKOP-15-2016-00037 project, the system consolidates all aspects of planning, from data access and negotiations to plan creation and approval into a centralized, web-based framework. The platform is powered by a 3D geospatial data infrastructure, which integrates planning hierarchies from national to municipal levels, ensuring coherence and consistency across territorial management. Its three core modules – Information, Reconciliation, and Planner – collectively provide planners, municipalities, decision-makers, and citizens with interactive tools for consultation, planning, and visualization. By creating a transparent and accessible digital ecosystem, E-TÉR not only simplifies complex workflows but also strengthens trust between institutions and the public.