All 15 Caching questions
More in Caching
What is caching, and why is it commonly used to improve the performance of a Node.js application? What is the difference between in-memory caching (like a Map or node-cache) and a distributed cache (like Redis)? What HTTP caching headers (Cache-Control, ETag) can a Node.js/Express API use to let clients and CDNs cache responses? How would you implement a Least Recently Used (LRU) cache in Node.js, and why is eviction necessary for an in-memory cache? What is memoization, and how does it differ from a general-purpose external cache like Redis? How would you cache the result of a database query in Node.js while ensuring the cache is properly invalidated when the underlying data changes? What is the risk of caching sensitive or user-specific data with a shared cache key, and how do you avoid it? What is negative caching, and why might you deliberately cache the fact that a lookup returned 'not found'? What are the main cache invalidation strategies (TTL, write-through, cache-aside), and when is each appropriate? What is cache stampede (thundering herd), and how do you prevent it in a high-traffic Node.js service?
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Node.js › Caching

What is the difference between res.set('Cache-Control', 'no-cache') and 'no-store' in an Express response?

Beginner

Answer

'no-cache' allows a cache to store the response, but requires it to revalidate with the origin server before reusing the cached copy on every subsequent request. 'no-store' is much stricter: it forbids storing the response at all, anywhere, appropriate for genuinely sensitive responses that must never be cached in any form.
// Allows caching but forces revalidation every time
res.set('Cache-Control', 'no-cache');

// Forbids storing this response anywhere at all
res.set('Cache-Control', 'no-store');
Real-world example A banking API sets Cache-Control: no-store on every endpoint returning account balance data, ensuring browsers, proxies, or any intermediate cache never retain a copy of that sensitive information.

Common follow-ups: How does a client know when a 'no-cache' response is safe to reuse versus needing to refetch it entirely?;Why would an application choose 'no-cache' over 'no-store' when it still wants some caching-related benefit?

Security;HTTP & HTTPS Modules
All 15 Caching questions