How Caching Saves Your Website From Thousands of Requests

Netflix delivers fast streaming experiences due to caching techniques. When you request a resource, it's temporarily stored in a faster location called the cache, so subsequent requests can access it quickly without repeatedly querying the database. This saves time and reduces workload on the server. Your web browser also uses caching for frequently accessed resources like images, CSS, and JavaScript files.

This way, when you revisit a site, your browser can pull those files from its local cache instead of downloading them again from the server. Content Delivery Networks (CDNs) take caching a step further by storing copies of content on servers distributed worldwide. So, when a user in India requests a resource, they often get it from a CDN server nearby rather than the US-based origin server.

This reduces latency and speeds up delivery. However, caching also introduces challenges like stale data if the underlying data changes after the cache expires. To mitigate this, developers often set expiration times (TTL) for cached items and implement cache invalidation strategies to ensure users always see the most up-to-date information.

One approach is to simply delete the cached entry and fetch fresh data from the database. Another is to update the cache whenever the source data changes. While caching significantly speeds up web applications, careful implementation is key to avoiding issues like stale data and maintaining data consistency.