Caching
Caching is a technique for storing frequently accessed data in fast, temporary storage to reduce the time and resources needed to retrieve it. Instead of repeatedly fetching data from slow sources (databases, external APIs, complex calculations), applications check the cache first and only go to the source when necessary. Caching happens at multiple levels: browser caches, CDN caches, application caches, and database caches. For non-technical readers, caching is like keeping commonly used items on your desk instead of walking to a filing cabinet each time. The first retrieval takes full effort, but subsequent accesses are nearly instant. This same principle, applied throughout software systems, dramatically improves speed and reduces load on underlying systems. Effective caching requires understanding what data changes frequently (shouldn't be cached long) versus what rarely changes (can be cached extensively). Cache invalidation, deciding when cached data is no longer valid, is notoriously challenging and requires careful design.
Official WebsiteWhen to use Caching
Use caching when the same data is requested repeatedly, when fetching data is expensive (slow database queries, external API calls), or when systems struggle to handle load. It's appropriate for nearly any application but requires thought about what to cache and how long to keep it.
Caching is particularly valuable for public websites with many visitors viewing similar content, for applications making repeated API calls, and for dashboards that aggregate data from multiple sources.
Why choose Caching?
Teams implement caching to improve performance and reduce costs. Faster responses improve user experience and search rankings. Reduced database load means smaller (cheaper) infrastructure can handle more users. Lower API call volumes reduce third-party service costs. Properly implemented caching often provides the best return on performance investment.