Caching and Background Updates with React Query

In most web applications, the same data is often fetched multiple times — for example, when users revisit a page, switch between tabs, or interact with components that rely on the same resource. Without a caching mechanism, each interaction triggers a fresh network request, wasting bandwidth and slowing down the interface.

Traditional approaches using fetch or Axios don’t handle this automatically. Developers often resort to manually storing data in global state or local storage to avoid unnecessary calls — a workaround that quickly grows messy and unreliable.

How React Query solves it

React Query changes this by introducing a built-in caching layer. Once data is fetched, it’s automatically stored in memory and instantly reused when requested again. Even better, React Query keeps the cache synchronized with the server — re-fetching data in the background when needed, such as when the browser tab regains focus or after a configurable “stale” period.

This means our app always feels fast and fresh without us writing any extra code for caching, synchronization, or refetching logic.

React Query uses the queryKey as a unique identifier for each cached query. Whenever the same key is requested again, React Query returns the cached result immediately while optionally updating it in the background.

It also manages stale time and cache time automatically:

• Stale time: How long the data is considered fresh before a background refetch is triggered.

• Cache time: How long unused data remains in memory before being garbage collected.

By fine-tuning these options, we can balance performance and freshness effortlessly — giving users near-instant responses with the confidence that their data is always current.