Adrian Hajdin is a Croatian developer and the founder of JavaScript Mastery, behind one of the larger React-and-Next.js tutorial YouTube channels. His personal-brand course material on CourseFlix sits alongside the JS Mastery catalog — both publishing long-form project-based React / Next.js builds.
The course catalog covers Next.js (including App Router, server components, server actions), React, TypeScript, Tailwind CSS, NextAuth / Clerk authentication, Prisma + PostgreSQL, Stripe billing, real-time features, the AI-feature integration patterns, and the deployment workflow with Vercel. Each course typically builds a complete working application end-to-end.
The CourseFlix listing under this source carries 8 Adrian Hajdin courses spanning that range. Material is paid and aimed at intermediate React developers building portfolio-quality projects.