JavaScript Mastery (jsmastery.pro) is the paid course platform of Adrian Hajdin, a Croatian developer behind one of the larger React-and-Next.js tutorial channels on YouTube. The channel and platform's distinctive contribution is long-form project-based clones — Netflix-style streaming app, Airbnb clone, Zoom clone — built end-to-end using the modern Next.js / React stack.
The course catalog covers Next.js (including App Router and server components), React, TypeScript, Tailwind CSS, Stripe billing, NextAuth / Clerk authentication, MongoDB / Prisma, React Native, and the AI-feature integration that has become a standard part of modern web applications. Material is paid extended versions of the YouTube content with additional features and depth.
The CourseFlix listing under this source carries 9 JavaScript Mastery courses spanning that range. Material is paid; the platform runs on per-course or membership pricing on the original platform. Courses are aimed at intermediate React developers building portfolio-quality projects.