Go past the API surface into fiber, concurrent rendering, and Server Components so your architecture calls are reasoned, not copied.
You know hooks, you know props, and the app still drops frames on a list of 500 rows. One context change repaints half the screen. An effect fires twice in dev and you added a ref to silence it without knowing why. A Server Component threw “you’re importing a component that needs useState” and you moved the 'use client' line until the error went away. That is React by rote, and it stops working the moment the app gets big. This course goes underneath the API. You trace the fiber linked list that makes hook order matter, watch the Scheduler interrupt a render, and see exactly what crosses the server/client boundary in RSC. You profile a real re-render storm and fix it with memo, virtualization, and structural changes — measuring each one instead of guessing. You build the component APIs shipped UI libraries actually use: compound, polymorphic, render props, state machines. Then you pick a state layer on purpose — TanStack Query for server state, Zustand or Jotai for client state, useSyncExternalStore for everything else — and harden it with error boundaries, accessibility audits, bundle budgets, and tests that exercise users rather than internals.
Built by Lakshya Kumar
Paste this into any AI chat. Fill in the bracketed parts with your context — you'll get back a straight answer on whether this belongs on your plate.
I am learning advanced React concepts — hooks internals, concurrent features, React Server Components, performance optimization, and state management patterns. Help me understand the deep 'why' behind React's design decisions, not just the API surface.
We grant free access case-by-case — students, career-switchers, builders on a tight budget. Sign in to send us a note.
Sign in to applyFinished the tasks? Take the prompt to your AI and get tested on it. We copy the prompt and open the app — just paste it in.
Know when extracting a hook actually pays, and how to make async, subscription, and cleanup logic testable in isolation.
Split providers, kill the unstable-object bug, and recognise the point where context is the wrong tool entirely.
Use the Profiler to find the actual hotspot instead of sprinkling useMemo everywhere and hoping the jank goes away.
Mark heavy work as interruptible with transitions and Suspense so a slow update stops swallowing the user’s keystrokes.
Draw the server/client boundary on purpose, cut request waterfalls, and know exactly what JavaScript reaches the browser.
Hunt the subscriptions, listeners, and stale closures that keep a long-lived tab growing until it crawls.
Build compound, polymorphic, and state-machine components the way shipped UI libraries do, with types that survive the flexibility.
Stop stuffing fetched data into useState — choose a cache, store, or subscription deliberately and know what it costs you.
Add the guardrails a shipped app needs: crash recovery, keyboard access, a bundle budget, and tests that click like a user.
Complete all modules, then submit the required number of capstone projects. Each must earn a passing rating from an admin reviewer.
Build a production-ready full-stack React application using React Server Components for data fetching, client components for interactivity, TanStack Query for optimistic mutations, and Zustand for UI state. The app must have error boundaries on every route, be fully keyboard-accessible (zero critical axe-core violations), have a main bundle under 200KB gzipped, and include component tests for the three most critical user flows.
Build a Next.js App Router project using React Server Components: streaming UI with Suspense, parallel data loading at the route level, error boundaries, and a measurement that shows TTFB and LCP under real network throttling. Include cache-tag invalidation flow.
Build a 4-step wizard form (10+ fields per step) with React Hook Form + Zod validation, dynamic dependent fields, server-side validation merged with client errors, abandon-and-resume state persisted to localStorage, and full keyboard navigation. Cover accessibility (WCAG AA) in tests.
Take a real (or example) React app with measurable jank and produce a profiling report: React DevTools profiler runs, identified re-render hotspots, three concrete optimizations applied (memo, virtualization, code split), and a before/after benchmark showing FCP and INP improvements.
Build a non-trivial UI flow (checkout, multi-step onboarding) using XState: visualized state machine, deterministic transitions, persistence + restoration, and a test suite that exercises every transition. Include the state diagram in your repo's README.