Cache
Temporary storage that speeds up data retrieval by keeping frequently accessed data closer to users.
Definition
A cache stores copies of data in temporary storage locations for faster access. Web caching happens at multiple levels: browser caches store files locally, CDN caches distribute content geographically, and server caches reduce database load.
Effective caching dramatically improves performance but requires strategies to ensure users see current content.
Why It Matters
Caching is fundamental to web performance. Without it, every page load would require full server processing and database queries, creating slow, expensive operations.
Understanding cache behavior helps troubleshoot why users might see outdated content or experience inconsistent experiences.
Examples in Practice
A CDN caches images and JavaScript files at edge servers worldwide, reducing load times for global users.
Browser caching stores logo and font files locally so returning visitors load pages faster.
Cache invalidation clears outdated content after a website update to ensure visitors see new designs.