Lesson 15 — Context vs Redux vs React Query | Choosing the Right Tool

🧭 Introduction

One of the most confusing decisions for React developers is:

❓ Which state management tool should I use?

Many developers:

• Use Redux everywhere
• Overuse Context API
• Misuse React Query
• Mix all three without understanding their roles

This leads to:
❌ Complex code
❌ Performance issues
❌ Hard-to-maintain applications

In this lesson, you’ll learn how senior developers choose between Context, Redux Toolkit, and React Query, and why using the wrong tool causes problems.

🎯 What You’ll Learn in This Lesson

By the end of this lesson, you will understand:

• The core purpose of each tool
• Differences between client state and server state
• When Context is enough
• When Redux Toolkit is required
• When React Query is the best choice
• A decision framework you can reuse in real projects

🧠 First: Understand Types of State (Very Important)

Before choosing tools, you must understand what kind of state you are managing.

🟢 1. UI / Client State

• Theme (dark / light)
• Sidebar open / close
• Modal visibility
• Selected tab

👉 Controlled fully by the frontend.

🔵 2. Global Client State

• Auth user info
• User role
• Language preference
• Feature flags

👉 Shared across many components.

🟣 3. Server State

• API data
• Lists from backend
• Pagination data
• Cached responses

👉 Lives on the server, can change anytime.

🧩 Context API — What It Is Best At

✅ What Context Does Well

Context is great for:

• Small global values
• UI-related shared state
• Configuration-like data

Examples:

• Auth status (basic)
• Theme
• Language
• Feature toggles

🔍 Example — Context for Theme

const ThemeContext = createContext();

function ThemeProvider({ children }) {
  const [theme, setTheme] = useState("light");

  return (
    <ThemeContext.Provider value={{ theme, setTheme }}>
      {children}
    </ThemeContext.Provider>
  );
}

Clean. Simple. Effective.

❌ When Context Becomes a Problem

Context is not ideal when:

• State updates frequently
• Data is complex
• Many components depend on it
• Performance matters

Why?

• Every update re-renders consumers
• No built-in devtools
• No structured async handling

👉 Context ≠ state management library.

🧩 Redux Toolkit — What It Is Best At

Redux Toolkit is designed for:

• Complex global client state
• Predictable state transitions
• Debugging with devtools

✅ Use Redux Toolkit When:

• State is large and complex
• Many unrelated components need the same data
• You need undo/redo, logging, time-travel debugging
• Business logic is heavy

Examples:

• Shopping cart logic
• Multi-step workflows
• Admin dashboards
• Permissions logic

🧠 Key Strengths of Redux Toolkit

• Centralized store
• Predictable updates
• Excellent devtools
• Structured async handling

Redux Toolkit shines for client-side business logic.

❌ When Redux Is Overkill

Avoid Redux when:

• State is local
• UI-only state
• Simple data sharing

Using Redux for:

const [isOpen, setIsOpen] = useState(false);

❌ is a mistake.

🧩 React Query — What It Is Best At

React Query is not a general state manager.

It is designed specifically for:
👉 Server State

✅ Use React Query When:

• Data comes from an API
• You want caching
• You need refetching
• Data can become stale

Examples:

• User lists
• Products
• Search results
• Dashboard metrics

🧠 Why React Query Is Special

React Query handles:

• Loading state
• Error state
• Caching
• Background refetching

All automatically — no reducers, no actions.

❌ When NOT to Use React Query

Do not use it for:

• UI state
• Form inputs
• Modal visibility
• Theme or auth UI flags

React Query is only for server data.

🆚 Context vs Redux vs React Query (Clear Comparison)

🧠 Decision Framework (Save This)

Ask these questions in order:

1️⃣ Is the data coming from a server?

➡️ YES → React Query

2️⃣ Is it complex global client logic?

➡️ YES → Redux Toolkit

3️⃣ Is it simple shared UI/config state?

➡️ YES → Context API

4️⃣ Is it local to one component?

➡️ YES → useState / useReducer

🏗️ Real-World Architecture (Professional Setup)

Most production apps use all three together:

Context API   → Theme, Auth UI
Redux Toolkit → Client business logic
React Query   → Server data

They are complementary, not competitors.

🚨 Common Mistakes (Very Important)

❌ Mistake 1: Using Redux for API Caching

React Query does it better.

❌ Mistake 2: Using Context for Frequently Changing Data

Leads to unnecessary re-renders.

❌ Mistake 3: Mixing Responsibilities

Each tool has a specific role.

❌ Mistake 4: Choosing Based on Popularity

Choose based on problem, not trend.

🎯 Best Practices (Senior-Level)

✅ Understand state types first
✅ Use the simplest tool possible
✅ Don’t fear mixing tools
✅ Let each tool do one job well
✅ Optimize for maintainability

❓ FAQs — Context vs Redux vs React Query

🔹 Can I use all three in one app?

Yes — and large apps often do.

🔹 Should beginners avoid Redux?

No, but learn Context and hooks first.

🔹 Is React Query replacing Redux?

No — it replaces Redux for server state only.

🔹 Can Context replace Redux?

Only for simple use cases.

🧠 Quick Recap

✔ Context → simple global state
✔ Redux Toolkit → complex client logic
✔ React Query → server state
✔ Wrong tool = messy app
✔ Right tool = scalable app

🎉 Conclusion

Choosing the right state management tool is a career-level skill.

Once you understand these differences:

• Your apps become cleaner
• Performance improves naturally
• Architecture decisions become easier

This lesson bridges the gap between learning tools and thinking like a React architect ⚛️🧠

👉 Next Lesson

Lesson 16 — React Query / TanStack Query (Server State Management)