Cache
also: caching, cached, caches
A saved copy of data kept somewhere quick to reach, so your app doesn't have to fetch or calculate it again every time.
A fast storage layer (memory, Redis, the browser, a CDN) holding copies of data that are slow to fetch or compute. Caches speed things up but can serve stale data, so they need rules for when copies expire or get cleared.
A sticky note with a friend's phone number on your desk, so you don't look it up each time. Fast, until they change their number and the note is wrong.
Caching is behind many "I changed it but it still shows the old thing" moments. When your agent adds caching for speed, ask how and when the saved copy gets refreshed.
The dashboard query takes 4 seconds, so I added a 5-minute cache. New orders may take up to 5 minutes to appear in the totals.
When a recipe is edited, clear its cached page so readers see the change right away. List every place we cache recipe data.
Treating the cache as where data really lives. It's a copy. The original lives elsewhere, usually the database, and the copy can fall behind.