Book excerpt: Fintech can improve sustainability, influence policies, and require new regulations. Climate change, water pollution, and non-renewable resources management can all be addressed with fintech innovations. Despite the advantages offered by fintech, opponents warn of potential negative consequences. The application of fintech in sustainability is a double-edged sword requiring further investigation. This book provides an overview of fintech applications and considers their impact on the future of sustainable finance. It explores how financial technologies can enhance the sustainability of investment and corporate decisions and contribute to the fulfillment of the Sustainable Development Goals (SDGs). By considering practitioner and academic views, it examines whether and how fintech can improve sustainable practices, potential threats with possible solutions, and policies and regulations designed to improve sustainability benefits.