Cache vs Local Storage vs Session Storage
Rupam Kumar Das
Product Support Engineer- Tier 2 | 6+ Years in IT Services | Expertise in Troubleshooting, Customer Success, and Technical Solutions | Passionate About Enhancing User Experience and Driving Operational Efficiency
Cache, Local Storage, and Session Storage are all mechanisms for storing data on the client side in a web browser, but they serve different purposes and have distinct characteristics. Here’s a breakdown of each:
?? 1. Cache:
- Purpose: Stores copies of web resources like HTML files, CSS stylesheets, JavaScript files, images, etc., to load websites faster on subsequent visits.
- Scope: Browser-wide, used across different sessions and tabs.
- Persistence: Data is stored until it expires (based on HTTP headers) or is manually cleared by the user.
- Use Cases: Speeding up website load times, reducing bandwidth usage.
?? 2. Local Storage:
- Purpose: Stores data that needs to persist across browser sessions without being sent to the server.
- Scope: Specific to the domain (origin) from which it was stored.
- Persistence: Data persists even after the browser is closed and remains until explicitly deleted by the user or through code.
- Size Limit: Typically around 5-10 MB per domain.
- Use Cases: Storing user preferences, settings, or state data that should persist across sessions, such as theme settings or form inputs.
?? 3. Session Storage:
- Purpose: Stores data that is needed only for the duration of the current browser session and is not required after the session ends.
- Scope: Specific to the window or tab in which it was stored; data is not shared between tabs or windows.
- Persistence: Data is cleared when the page session ends, typically when the tab or browser is closed.
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- Size Limit: Typically around 5 MB per domain.
- Use Cases: Storing temporary data like session-specific state, form data that should not persist after the session, or data that is specific to a single page view.
?? Summary Comparison:
- Cache:
- Lifetime: Until expiration or manual clearance.
- Scope: Browser-wide, across sessions.
- Data Type: Web resources (HTML, CSS, JS, etc.).
- Local Storage:
- Lifetime: Persistent until explicitly deleted.
- Scope: Domain-specific, across sessions.
- Data Type: Key-value pairs, typically for application data.
- Session Storage:
- Lifetime: Until the session ends (closing the tab or browser).
- Scope: Tab/window-specific, not shared between tabs.
- Data Type: Key-value pairs, typically for session-specific data.
These mechanisms allow web developers to manage data on the client side efficiently, choosing the right storage solution based on the nature of the data and the desired persistence.