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Mursal Furqan Kumbhar
Mursal Furqan Kumbhar

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🚀 Scaling React Like Big Tech: Folder Structures, Clean Code & Beyond

#webdev #programming #javascript #beginners

Hey Everyone 👋

I know it's been quite a long gap since my last article. But we are finally back with a bang.

So if you’ve ever wondered how Airbnb, Shopify, or Meta keep their codebases sane while thousands of engineers ship features daily — the answer is simple: structure + discipline + automation.

This isn’t about writing code that just works. It’s about writing code that:

  • Scales with your team.
  • Survives onboarding of 10 new devs.
  • Passes reviews without a hundred nitpicks.
  • And doesn’t make you cry when you open it six months later.

Let’s break down what the big companies do differently — and how you can bring those practices into your own projects.

📂 Folder Structure that Scales

Top companies don’t just throw files into a random components/ folder and hope for the best. They use feature-driven architecture, which grows naturally with the product.

❌ Traditional (Bad) Structure 

src/
├── components/
│   ├── Button.jsx
│   ├── Card.jsx
│   ├── Form.jsx
├── services/
├── hooks/
└── App.jsx
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This looks fine at first… until your app has 300+ components and no one knows which belongs to what.

✅ Scalable (Feature-Based) Structure 

src/
├── features/
│   └── auth/
│       ├── components/
│       ├── hooks/
│       └── services/
├── shared/
│   ├── ui/
│   └── utils/
└── App.jsx
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📌 Key Difference: Everything related to a single feature (Auth, Products, Cart, etc.) is grouped. Shared logic/components live in shared/.

Approach Pros Cons
Traditional (by type) Simple to start Becomes chaos at scale
Feature-Based Easy ownership, scalable, testable Slightly more setup upfront

🎨 Design Systems & UI Libraries

Big companies don’t reinvent the button every Tuesday. They use design systems and UI libraries.

  • 🚀 Airbnb → Lona
  • 🚀 Shopify → Polaris
  • 🚀 Meta → Reusable UI + strict guidelines

👉 Tools you can use: Chakra UI, Tailwind + Headless UI, Radix UI

Visual Example

❌ Without Design System:

<Button variant="danger" color="red" bg="red" />
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✅ With Design System:

<DeleteButton />
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Why Use Design Systems? Benefits
Consistency UI looks the same across app
Speed Devs move faster
Accessibility Built-in ally support
Brand Identity Product feels cohesive

🧑‍💻 Hooks = Where Logic Lives

Business logic doesn’t belong inside components. Custom hooks make code reusable, testable, and clean.

Example: 

// useProduct.js
export function useProducts() {
   const [data, setData] = useState([])
   useEffect(() => {
      fetchProducts().then(setData)
   }, [])
   return data
}
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✅ UI stays declarative.
✅ Logic stays modular.

📊 Diagram: Components vs Hooks

[Component] ---> UI (render)
       |
       v
 [Custom Hook] ---> Data Fetching, State, Business Logic
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🧼 Clean Code = Scalable Code

Big tech engineers follow clean code principles:

  • SRP → Single Responsibility Principle
  • KISS → Keep It Simple, Stupid
  • DRY → Don’t Repeat Yourself
❌ Bad ✅ Good
<Button variant="danger" color="red" bg="red" /> <DeleteButton />

✅ Abstraction = Fewer Bugs + Cleaner Reviews

🔍 Real-Time Code Reviews + Linting

At big companies, automation + reviews are mandatory.

  • ✅ Code Reviews → shared knowledge
  • ✅ Pre-Commit Hooks (Husky) → catch errors early
  • ✅ ESLint + Prettier → consistent style

CI/CD Pipeline Visual 

[Developer Pushes Code] 
       |
       v
[Pre-Commit Checks: Lint + Tests]
       |
       v
[Pull Request Review]
       |
       v
[CI/CD: Build + Deploy + Monitor]
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🔐 Security & ♿ Accessibility First

Security isn’t optional. Accessibility isn’t either.

Security Checklist

  • Prevent XSS and CSRF
  • Proper token handling
  • Input validation

Accessibility Checklist

  • Keyboard navigation works
  • Screen reader support
  • High color contrast

👉 Use tools like axe-core, eslint-plugin-jsx-ally, lighthouse.

⚡ Automation + Monitoring

Big teams don’t just ship code — they ship pipelines + monitoring.

  • ✅ CI/CD Pipelines (GitHub Actions, Vercel, CircleCI)
  • ✅ Bundle Size Alerts
  • ✅ Error Tracking (Sentry, Datadog)
  • ✅ Performance Monitoring (Lighthouse CI)

📊 Example:

Commit → Build → Test → Deploy → Monitor
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📊 Documentation & Knowledge Sharing

What separates side projects from real companies?
👉 Documentation.

  • Good README.md = contributor-friendly.
  • Internal wikis = no lost knowledge.
  • ADRs (Architecture Decision Records) = explain why choices were made.

🧠 Culture = The Invisible Architecture

Finally — even the best code structure won’t save a bad culture. Big companies win because:

  • PRs = conversations, not fights.
  • Automation is embraced, not skipped.
  • Docs + testing = part of “done”.

At the end of the day, how your team codes together matters more than folder names.

🚦 Startup vs Big Tech Codebases

Here’s how things usually look in a scrappy startup vs how big tech organizes for scale:

┌────────────────────┐           ┌─────────────────────────┐
│   Startup Style    │           │     Big Tech Style      │
├────────────────────┤           ├─────────────────────────┤
│ 📂 components/     │           │ 📂 features/auth/       │
│ 📂 hooks/          │           │   ├── components/       │
│ 📂 services/       │           │   ├── hooks/            │
│ App.jsx            │           │   └── services/         │
│                    │           │ 📂 shared/ui/           │
│ Easy to start ✅   │           │ 📂 shared/utils/        │
│ Chaos later ❌      │           │ Scales across teams ✅  │
└────────────────────┘           └─────────────────────────┘
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📊 Side-by-Side Table

Aspect Startup-Style Big Tech-Style
Folder Structure Flat, all components in one folder Feature-based, modular
UI Custom each time Design system + UI library
Logic Inside components Extracted into hooks
Code Quality Quick fixes, less abstraction Clean code, reusable patterns
Reviews Ad-hoc, sometimes skipped Mandatory PRs + linting + tests
Security Later concern Built-in from day one
Docs README only Wikis + ADRs + onboarding guides
Culture “Move fast, break things” “Move fast, don’t break prod”

🎯 Final Takeaway

Big companies scale not because their engineers are magical unicorns 🦄, but because they follow battle-tested practices:

  • Organize code by features, not file types.
  • Use design systems for UI.
  • Extract logic into hooks.
  • Follow clean code principles.
  • Automate reviews + pipelines.
  • Prioritize security & accessibility.
  • Write documentation.
  • Build a team culture around consistency.
  • Startups often optimize for speed, but end up with technical debt.
  • Big Tech optimizes for scalability, making onboarding, reviews, and growth smooth.
  • The sweet spot? Start with startup speed, but gradually adopt Big Tech practices before chaos hits.

Happy Hacking 👋

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