This tutorial demonstrates how to develop a multi-tenant Next.js 14 application for generating digital coupons using OpenAI's API, secured with PropelAuth for authentication. The application allows authorized users, specifically grocery store managers, to create on-demand digital coupons by entering a discount percentage and assigning a store name, with the frontend and backend components built on Next.js. PropelAuth is integrated to ensure only authorized personnel can access the coupon generation feature, utilizing roles and permissions to restrict access to store managers and owners, while also protecting the API endpoint. The process involves setting up user authentication, implementing frontend form handling, and securing API requests by verifying user roles and organization affiliations, with the complete code available on GitHub for further exploration and customization.