This book constitutes the proceedings of the 1st Congress in Sustainability, Energy and City (CSECity?21) held in Ambato, Ecuador, on June 28?29, 2021, proudly organized by Universidad Tecnológica Indoamerica in collaboration with GDEON. The CSECity brings together experts that promotes the dissemination of advances in sustainability, urbanism, energy, and industry research through the presentation of keynote conferences. In CSECity,  theoretical, technical, or application works that are research products are presented to discuss and debate ideas, experiences, and challenges. Presenting high-quality, peer-reviewed papers, the book discusses the following topics: Energy sustainability Information and knowledge management Information technologies Innovation, technology, and society Software and systems modeling Software systems, architectures, applications, and tools Sustainable energy and the city.