Caching strategies that speed up your backend
If your app is slow or your bills are high, caching is often the highest-leverage fix. The idea is simple: don't redo work you've already done. Here's how to think about it without getting lost in the weeds.
Why caching works
Most apps repeat the same work constantly — fetching the same data, rendering the same page, running the same query. Caching stores the result the first time, then serves it instantly afterwards, until it changes. The effect on speed and cost can be dramatic.
Where you can cache
- In the browser. Store assets and data on the user's device so repeat visits are instant.
- At the edge / CDN. Serve content from servers close to the user, worldwide.
- In the application. Keep frequently-used data in fast memory instead of recomputing it.
- At the database. Cache expensive query results so they aren't run repeatedly.
The hard part: keeping it fresh
"There are only two hard things in computing," the joke goes, "and one of them is cache invalidation." The challenge isn't caching — it's knowing when cached data is stale and needs refreshing. Cache things that don't change often, set sensible expiry, and have a clear way to refresh when the underlying data changes. Done carelessly, caching shows users out-of-date information.
The fastest work is the work you don't redo.
- Caching reuses expensive results to make apps faster and cheaper.
- You can cache in the browser, at the edge, in the app, and at the database.
- The hard part is freshness — set sensible expiry and a way to refresh.
Frequently asked questions
Will caching make my app show stale data?
It can if done carelessly. The trick is caching things that don't change often and having a clear way to refresh when the underlying data changes.
Is caching only for big apps?
No — even small apps benefit. A little caching of common requests or assets often delivers a big, cheap performance win.
What's the easiest caching win?
Usually a CDN for your static assets and pages — fast to set up and immediately makes your site faster worldwide.
ZIVARA makes software fast and cost-efficient — caching included where it counts. Let's talk. Related: fixing Core Web Vitals.