When beginners start learning React js, they quickly understand the basics of state but soon hit a wall:
"Where should this data live?"
"Should this be local state or global state?"
"Why am I passing the same data through 5 components?"
"Why is my app getting harder to manage as it grows?"
This confusion is normal.
State management is one of the most important and most misunderstood topics in React. Understanding state isn't enough; you must understand what kind of state you're working with.
This blog simplifies two major categories:
Local State
Global State
Once you understand the difference, your React apps will instantly become cleaner, more organized, and easier to maintain.
Let's begin at the foundation.
State is the memory of a component.
It represents:
values that change over time
data that updates the UI
information UI Full-Stack web with React should track and re-render with
Any dynamic part of your UI input text, toggles, items in a list, active user, theme is controlled by state.
But not all state belongs in the same place.
That's where local vs global state comes in.
Local state is state that belongs to a component and is only relevant inside that component.
Examples of local state:
A text field value
A toggle (open/close)
A modal's visibility
A selected tab
Temporary UI filters
A loading spinner
Form validation status
Local state answers:
"This component needs some memory of its own."
Local state is small, simple, and directly tied to the behavior of the component.
Global state is state that needs to be shared across multiple components, especially components that are not directly related.
Examples of global state:
Logged-in user information
Application theme (light/dark)
Shopping cart items
Notifications
Auth tokens
Language/locale
Global filters
Data fetched once and reused in multiple places
Global state answers:
When many components need the same data, local state becomes insufficient.
Lives inside one component
Only that component cares about it
Does not affect distant components
Easy to manage
Shared by many components
Exists outside any single component
Affects multiple screens, pages, or features
More complex, requires a structured approach
In simple terms:
Local state is private.
Global state is shared.
Beginners often make one of two mistakes:
This leads to:
long chains of props
passing data through components that don't use it (prop drilling)
hard-to-maintain structures
This leads to:
unnecessary re-renders
slower performance
complex state management
global data that should be isolated
Use local state unless the data must be shared.
Use global state only when necessary.
Let's explore scenarios to understand what should be local vs global.
You click the menu → it opens.
Does any other component care?
No.
→ Local state.
Do multiple components need access?
Yes navbar, profile page, dashboard, sidebar, etc.
→ Global state.
If only this page needs the filter:
→ Local state.
Used across the entire UI.
→ Global state.
Only the form uses it.
→ Local state.
Visible and needed across many pages.
→ Global state.
If only the screen controls the modal:
→ Local state.
If multiple components trigger or monitor the modal:
→ Global state.
Only that component cares countdown, stopwatch.
→ Local state.
Multiple pages need to display notifications.
→ Global state.
Some steps may need data from others.
→ Global state (but can also be grouped in a parent component).
Local state:
belongs to the component instance
lives inside React's Fiber structure
triggers re-render only for that component
is easy to track and manage
Local state is ideal for performance because:
it affects only one component
React can optimize it aggressively
changes do not ripple unnecessarily
Think of local state as a small private notebook the component carries.
Global state:
is stored outside any single component
can be consumed by many components
triggers re-renders in all subscribed components
needs structured management to avoid chaos
Global state solutions typically use:
React Context
Redux
Zustand
Jotai
Recoil
MobX
These tools organize shared state and help React know:
which components depend on which values
when they must re-render
how to keep the UI consistent
how to avoid unnecessary renders
Global state is powerful but must be used carefully.
Local state is simpler.
Local state is faster.
Local state avoids complexity.
Local state helps isolate logic.
Most React experts follow this principle:
"Keep state as close to where it's used as possible."
Do not move state to global level unless several components need it.
This avoids:
over-engineering
unnecessary context
global clutter
performance drops
Some types of data MUST be global because they must remain consistent across the entire app.
Global state is required when:
Multiple components read the same data
Actions in one place affect other places
Data must persist across routes or pages
The app has a shared session or theme
Many features depend on the same data source
Examples:
User authentication
Application theme
Shopping cart
Notifications
Global API results
Multi-screen onboarding data
Prop drilling happens when you pass data through components that don't need it, just so deeper components can use it.
Example:
App → Page → Section → Box → Component → Child
Only the last one needs the data.
Signs you're prop drilling:
passing the same prop through multiple components
components receiving props they don't actually use
your code feels like a chain of forwarding
This is a major sign you need to:
lift state up
or move it to global state
or create context
In complex apps:
the user should not appear logged out in one component and logged in somewhere else
the shopping cart should match across all pages
the selected language/theme must be consistent
Global state provides one central truth that the entire app respects.
Without this:
UI becomes inconsistent
components get out of sync
debugging becomes painful
Global state ensures consistency.
Global state can cause many components to re-render at once.
This is the downside.
Because:
if a global value changes
all components that depend on it re-render
This is why global state must be used sparingly.
Tools like Redux, Zustand, and Context have techniques to minimize unnecessary re-renders but it's still heavier than local state.
React Context is built into React.
It allows you to:
create global values
share them across the app
avoid prop drilling
Context is great for:
theme
language
auth
user settings
light global data
But context is not ideal for:
large global data
frequently updated values
performance-heavy scenarios
This is when external global state libraries are needed.
When you plan your component structure, think in layers:
form input
modal open/close
active tab
selected menu item
lift state up to the nearest common parent
data needed everywhere: theme, user, cart
This layered approach keeps apps clean and manageable.
Let's break an e-commerce app into state types.
product image zoom toggle
local sorting preference
quantity selector
modal previews
star rating hover state
list filters for a specific page
product page tab selection
user logged-in status
cart items
total quantity
theme
selected currency
This example shows why mixing everything into one bucket is a mistake.
like animation toggle
comment input
story viewer open state
current user
notifications
unread message count
theme
app language
active sidebar item
chart filter
modal visibility
user role (admin/user)
global settings
global API cache
access permissions
A small React js app can survive with poorly placed state.
A large app cannot.
Symptoms of poor state placement:
random bugs
inconsistent UI
multiple components showing outdated data
complicated prop chains
unexpected re-renders
difficulty adding new features
unpredictable behavior
Correct state placement makes an app scalable.
Here's the golden rule:
Start with local state.
Move to global state only when necessary.
Ask yourself:
Does more than one component need this data?
→ Consider global.
Does this data affect the whole UI?
→ Global.
Is only one component responsible for it?
→ Local.
Am I passing props down too many levels?
→ Global or lifted state.
This simple rule will guide 80% of decisions correctly.
Local state keeps components focused and simple.
Global state keeps applications organized and consistent.
You need both.
The key is knowing:
which state belongs where
when to promote state to a higher level
how to avoid clutter and confusion
how to structure state for scalability
Once you understand this separation, React development becomes:
smoother
cleaner
more predictable
easier to scale
easier to debug
architecturally sound
State management is not about tools it's about clarity.
Get clarity about local vs global state, and every React project becomes manageable.
Local state belongs to one component; global state is shared across multiple components.
No. Use global state only when several parts of the app need the same data.
Passing props through multiple components that don't use them a sign you may need global state or lifted state.
Yes for small to medium apps. For large apps with heavy data or frequent updates, use libraries like Redux or Zustand.
Yes unnecessary re-renders can occur if used incorrectly.
Always start with local state. Move to global when required.
No. Many small apps can work perfectly with only local and lifted state.
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