Cache

Stored copies of a response, kept so the next request can be answered without rebuilding it.

Set explicit cache headers per asset type: long lifetimes with fingerprinted filenames for static files, short and revalidated for HTML.

Plan invalidation before launch. A cached page nobody can clear is how stale prices reach customers.

Caching is usually the difference between a fast site and a fast server bill.

It protects both repeat visitors and crawlers from paying the full cost of rendering every time.