Think before you cache | SINAPTIA

“Maybe we should cache this”. It’s a common thought when we notice a slow response or an expensive computation. Just as common - and even more frustrating - is the follow-up thought: “Must be the cache”. That moment when something returns an unexpected response, a stale value in a view, a wrong number in an API response, or a method returning outdated or just plain incorrect data. And the culprit? Caching gone wrong. Most Rails apps are already leveraging caching from the get-go, even if it’s not immediately obvious. For example, digested assets (like stylesheets, JavaScript files, and logos) are fingerprinted and cached by the browser to avoid re-downloading them on every visit. Turbo Drive also caches full pages in memory by default, enabling near-instant back and forward navigation. Let’s explore common caching strategies and gems available in Ruby on Rails, but first, let’s take a step back to understand the purpose of caching and where it fits into a well-architected Rails app. After all, anything can be cached, but not everything should be.