What are the differences between cookie, local storage and session storage?
Assesses fundamental understanding of JavaScript conventions, runtime behavior, and memory/performance considerations.
Hiring managers look for precision, avoidance of ambiguous jargon, and ability to explain trade-offs under real production conditions.
Below are some of the differences between cookie, local storage and session storage,
| Feature | Cookie | Local storage | Session storage |
| --------------------------------- | ------------------------------------------------------------------------------------------------------------------- | --------------------- | ------------------- |
| Accessed on client or server side | Both server-side & client-side. The set-cookie HTTP response header is used by server inorder to send it to user. | client-side only | client-side only |
| Expiry | Manually configured using Expires option | Forever until deleted | until tab is closed |
| SSL support | Supported | Not supported | Not supported |
| Maximum data size | 4KB | 5 MB | 5MB |
| Accessible from | Any window | Any window | Same tab |
| Sent with requests | Yes | No | No |
Candidate Response Strategy & Interview Tips
- Start with a concise one-sentence summary: Deliver a direct, confident answer first before expanding into nuances.
- Demonstrate real-world trade-offs: Discuss where this approach excels and when you would avoid it in production systems.
- Discuss complexity & edge cases: Proactively explain time/space complexity or boundary conditions (null values, scale limits).
- Prepare for interviewer follow-ups: Technical hiring panels frequently probe deeper into concurrency, backward compatibility, or alternative libraries.