Integrating Descope, Next.js, and Supabase allows developers to build secure and scalable applications with streamlined authentication and authorization processes. This guide demonstrates how to implement these technologies to create a "todo list" app with robust security features. Descope provides flexible, no-code authentication with enhanced security measures like multi-factor authentication, while Supabase, built on Postgres, offers backend services including real-time databases and serverless functions. A critical feature of Supabase is Row Level Security (RLS), enabling fine-grained access control by defining policies based on user attributes, ensuring users access only their data. In this setup, Descope handles authentication, and Supabase manages authorization through RLS, offering a secure architecture with minimal complexity. The guide details the integration process, highlighting the use of the Descope Next.js SDK for user authentication and Supabase's capabilities to enforce access control at the database level, ensuring data segregation and privacy. This approach not only simplifies the developer experience but also opens avenues for extending these principles to more complex applications, such as AI systems and multi-tenant platforms.