Browser storage options serve different needs. Here's how to choose and use each effectively.
Storage Comparison#
| Feature | Cookies | localStorage | sessionStorage | IndexedDB |
|----------------|--------------|--------------|----------------|--------------|
| Capacity | 4KB | 5-10MB | 5-10MB | 50MB+ |
| Persistence | Configurable | Permanent | Tab session | Permanent |
| Sent to server | Yes | No | No | No |
| Sync/Async | Sync | Sync | Sync | Async |
| Data type | String | String | String | Any |
localStorage#
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sessionStorage#
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IndexedDB#
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Cookies#
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When to Use What#
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Storage with Expiration#
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Best Practices#
Security:
✓ Never store sensitive data unencrypted
✓ Use httpOnly cookies for auth tokens
✓ Set appropriate cookie flags
✓ Validate stored data
Performance:
✓ Don't store too much in localStorage
✓ Use IndexedDB for large data
✓ Batch IndexedDB operations
✓ Clean up expired data
Reliability:
✓ Handle storage quota errors
✓ Provide fallbacks
✓ Validate JSON parsing
✓ Test private browsing mode
Conclusion#
Choose storage based on data size, persistence needs, and whether the server needs access. localStorage for small persistent data, sessionStorage for tab-specific temporary data, IndexedDB for large datasets, and cookies when the server needs the data.