An OpenAI-powered flashcard learning application where users can: create and organize flashcard decks for studying, study cards with a flashcard interface, generate flashcards automatically using AI (OpenAI), and access based on subscription tiers (Free vs Pro). The next tech stack was implemented – Next.js 15+ (App Router), TypeScript, UI: React + Tailwind CSS + shadcn UI, Auth & Billing: Clerk (with Clerk Billing for subscriptions), Database: PostgreSQL (Neon) with Drizzle ORM, AI: Vercel AI SDK + OpenAI (GPT-4 Turbo).