What You’ll Gain Inside the Course

Learn the patterns and trade-offs behind professional frontend architecture — not just how to code, but how to design.

  • Confidence to design scalable frontend systems instead of patching features together.

  • A clear framework for data modeling, fetching, mutation, and rendering strategies.

  • Hands-on practice with real-world patterns you’ll actually use at work.

  • A capstone project you can showcase in your portfolio or interviews.

  • The mindset and skills to think like a senior engineer and make trade-offs wisely.

Watch the introduction

Discover what you’ll learn in this course in just 2 minutes

Course curriculum

    1. Welcome & Course Roadmap

    2. Course Starter Repository

    3. Walk Through the Starter Project

    4. Checkpoint: Rendering Your First Avatar from the API

    5. How to Learn Effectively in This Course

    6. Frontend System Design Common Pitfalls

    1. Understand Why Data Modeling Matters

    2. Case Study — Modeling “Features” on a Menu Item

    3. Normalization - Identifying the Real Problem

    4. Normalization in Practice — Step-by-Step Refactor

    5. Fixing A Defect We Introduced

    6. Checkpoint - AssigneeList — Before & After Normalization

    7. Build the AssigneeList for Real (Step-by-Step)

    8. How Backend Databases Handle Normalized Data

    9. Evaluating Trade-offs in Store Design

    10. Quiz - Data Modelling

    1. Introducing Data Fetching

    2. Requests Management: Request Cancelation

    3. Requests Management: Debounce & Throttling

    4. Quiz - Requests Management

    5. Pagination Strategies: Offest-based, Cursor-based and Infinite Scrolling

    6. Implement Pagination in The Board Application

    7. Caching Strategies in Frontend Applications

    8. Quiz - Fetching Data Efficiently

    1. Introducing Data Mutation

    2. Checkpoint - Implementing Deletion

    3. Assigning a User to a Card (Code Implementation)

    4. Real-Time Updates Patterns

    5. Real-Time Updates – Polling, SSE, and WebSockets

    6. Real-Time Updates in Action - Using Server-Sent Event

    7. Building Optimistic UI with Rollback

    8. Quiz - Mutating and Synchronizing Data

    1. Introducing Performance Enhancement

    2. Rendering With The Right Strategy

    3. Server-Side Rendering In Action

    4. Enhancing Perceived Performance

    5. Implementing Skeleton Pattern in Board View

    6. Prefetching Data When User Shows Intention

    7. Introducing Lazy Loading

    8. Checkpoint - Lazy Loading List View

    9. Measure and Improve Performance

    10. Quiz - Optimizing Performance

    1. Optimizing Performance with HTTP Caching

    2. Testing Strategy and Unit Testing Essentials

    3. End-to-End Testing the Feature with Playwright

    4. Frontend Security: Understanding XSS

    5. Frontend Security: Applying CSP Effectively

    6. Frontend Security: Sanitizing User Input Safely

    7. Quiz - Frontend Security

    8. Designing for Inclusivity and Accessibility

    9. Handling Failures with Error Boundaries

About this course

  • $119.00
  • 62 lessons
  • 6 hours of video content

Who This Course Is For

This course is designed for mid to senior frontend engineers who already build applications with React (or similar frameworks), and want to design scalable systems, not just features.. If you’ve ever struggled with messy state, unclear data flows, or performance bottlenecks, this course will give you the patterns and mental models to handle them with confidence.
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Instructor

Developer / Author / Creator Juntao Qiu

Hi, I’m Juntao — a seasoned software developer focused on clean architecture, performance, and frontend system design. I’ve seen how messy state, poor data flows, and short-sighted rendering decisions can sink projects, and my mission is to help developers avoid those traps. Through my books Test-Driven Development with React (2021), Maintainable React (2022), and React Anti-Patterns (2024), as well as my YouTube channel I Code It, I share practical techniques for refactoring, testing, and building scalable frontend applications. My goal is simple: to help you think like a system designer, not just a feature builder, and grow into a confident senior-level engineer.

Think in Systems, Not Just Components

Most developers are trained to build features like search boxes or dashboards, but as apps grow these pieces don’t exist in isolation — they live inside a system of data models, fetching and mutation patterns, rendering strategies, and infrastructure. This course helps you connect those dots so you can design scalable, maintainable frontend systems instead of patching features together.
Thinking in system

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Enroll today to gain the skills, mindset, and project experience that employers look for in senior engineers.

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FAQ

  • What learning style can I expect?

    A mix of pre-recorded videos, coding assignments, quizzes, and written guides. Each module has hands-on exercises, not just theory.

  • How is this different from free YouTube content?

    My channel focuses on bite-sized tips. This course is a structured system that takes you from feature-building to system design — with projects, exercises, and a full learning path.

  • I have a frontend system design interview coming up. Will this help?

    Yes. The first module introduces a clear structure for thinking about frontend system design, which can help you organize your answers and communicate trade-offs more clearly in an interview. If you’re short on time, you can also focus on specific topics you’re less confident about, such as data modeling, pagination, caching, or performance. While system design is something you develop over time, this course is designed to help both in interviews and in real-world work.

  • What if I’m not sure I’ll like it?

    No worries — the course comes with a 100% money-back guarantee if you don’t find it valuable after the first two modules.

  • What kind of project will I build?

    You’ll build a board-style application that evolves as you learn each concept — from data normalization to performance optimization. By the end, you’ll have a portfolio-ready project you can showcase in interviews or performance reviews.

  • What’s the time commitment?

    About 8–10 hours of core material, plus extra time for coding challenges and the capstone project. You can learn at your own pace.

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