Caching
Caching is the process of storing copies of data or files in a temporary storage location so future requests for that data can be served faster without regenerating or re-fetching it.
Caching stores frequently accessed data in a location where it can be retrieved more quickly than from the original source. In web development, caching happens at multiple levels, and each layer can dramatically improve performance. Browser caching stores static assets (images, CSS, JavaScript) on the user's device.
This is controlled through HTTP headers like Cache-Control and ETag. Server-side caching stores the results of expensive operations (database queries, API calls, page rendering) so they don't need to be repeated. Popular tools include Redis and Memcached.
In practice
- A WordPress site implemented full-page caching and went from handling 100 concurrent users to 10,000 without any server upgrades
- An e-commerce platform cached their product catalog with Redis, reducing database queries from 500 per page load to 5, and cutting page load time by 70%
- A news website uses browser caching with a 1-year expiration for versioned static assets, making returning visitor page loads nearly instant
- A SaaS dashboard caches frequently accessed reports for 5 minutes, reducing compute costs by 95% while keeping data reasonably fresh
Not sure how this applies to you?
A senior engineer walks your site, your search presence and the way enquiries reach you, then writes down the three things worth fixing first. You keep the document either way.