Discover how to use caching to dramatically reduce load times and decrease server load.
Caching is the practice of storing copies of files or data in a temporary storage location—a 'cache'—so that they can be accessed more quickly. Effective caching is one of the most impactful ways to improve application performance. We'll explore two main types: client-side and server-side. Client-side caching happens in the user's browser. By setting appropriate HTTP headers like `Cache-Control`, you can instruct the browser to store static assets (like CSS, JavaScript, and images) locally, so it doesn't have to re-download them on subsequent visits. Service Workers (covered more in PWAs) offer even more powerful client-side caching abilities, enabling offline access. Server-side caching involves storing data closer to the application logic. A Content Delivery Network (CDN) is a form of server-side caching that distributes your static assets across a global network of servers. Other strategies include in-memory stores like Redis or Memcached to cache frequent database query results, reducing database load and speeding up API responses. A critical challenge in caching is 'cache invalidation'—the process of ensuring that when data changes, the outdated cached copies are removed or updated.