localStorage VS sessionStorage

JavaScriptJunior~1 min read

The main difference

Property	localStorage	sessionStorage
Storage time	Data is kept forever, until the user clears it or code removes it	Data is kept only while the tab/window is open
After a page reload	Kept	Kept
After closing the tab	Kept	Removed
Shared access between tabs of the same domain	Yes	No (each tab has its own storage)
Capacity	~5-10 MB	~5 MB
Data type	Strings only (uses `JSON.stringify`)	Strings only (also via `JSON.stringify`)
Access restriction	Same domain only	Same domain and same tab only
Common use	Themes, settings, tokens, cached data	Temporary state, filters, drafts, session tokens

Code example (the same API)

javascript

// localStorage
localStorage.setItem('theme', 'dark');
console.log(localStorage.getItem('theme')); // "dark"

// sessionStorage
sessionStorage.setItem('step', '2');
console.log(sessionStorage.getItem('step')); // "2"

After closing the tab:

localStorage -> the value remains,
sessionStorage -> it is cleared automatically.

When to use which

localStorage - for "long-lived" data

Use it when data needs to survive after the browser is closed:

the chosen theme (dark/light),
a remembered login,
a shopping cart,
user settings.

sessionStorage - for "temporary" data

Use it when you need to store state within a single session:

temporary forms and filters,
the step state in a registration wizard,
a session auth token.

Example of a practical difference

javascript

// in the first tab
localStorage.setItem('color', 'red');
sessionStorage.setItem('page', 'home');

// in a second tab of the same site:
console.log(localStorage.getItem('color')); // "red" available
console.log(sessionStorage.getItem('page')); // null not available

Short summary

Storage	Lives	Shared data between tabs	Removed
localStorage	forever	yes	manually or by clearing the browser
sessionStorage	while the tab is open	no	when the tab is closed

Remember it simply:

localStorage is persistent storage (for "long-lived" data).

sessionStorage is temporary storage (for the "current session").

Short Answer

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localStorage VS sessionStorage

#The main difference

#Code example (the same API)

#When to use which

#localStorage - for "long-lived" data

#sessionStorage - for "temporary" data

#Example of a practical difference

#Short summary