This paper examines the role of Positive Energy Districts (PEDs) in the context of sustainable energy transition in the urban landscape. It collects Key Performance Indicators (KPIs) from different European projects to determine which are the most important aspects for monitoring, planning and implementing effective PEDs. A PED is a neighborhood able to generate more energy than it consumes producing net zero GHG emissions. Furthermore, it exports the surplus energy outside its boundaries. After a literature review of various PED definitions, this work explores PED typologies, the technologies involved in them, and the associated challenges. This study advocates for a flexible and adaptable KPI framework in recognition of the diversity of PEDs influenced by geographical, climatic, and urban structural variations. The work gathered 243 KPIs from 11 European initiatives and classified them into 5 macro-categories. The mapped KPIs provide a strategic guide for policymakers, planners, and stakeholders for steering urban areas towards carbon neutrality. Positioned not only as energy hubs but also as catalysts for improving urban life quality, PEDs embody broader societal goals, which are intertwined with sustainable energy transition. The research contributes to the ongoing dialogue on PEDs, providing a foundational framework for empirical investigations and fostering continuous innovation. This paper envisions PEDs as pivotal contributors to the global pursuit of urban sustainability, offering a transformative paradigm for the future of urban energy landscapes.