How Caching Works

The core idea

Caching means keeping a reusable copy of something so it does not have to be generated or fetched from scratch every time.

Caches are used across browsers, websites, APIs, databases, CDNs, and applications.

When something is cached, a later request can often be served from the cache instead of hitting the original slower source.

This can reduce latency, save resources, and improve consistency under load.

How it works step by step

When something is cached, a later request can often be served from the cache instead of hitting the original slower source.

This can reduce latency, save resources, and improve consistency under load.

Caching matters because it is one of the most common ways to improve performance and reduce repeated work.

It affects how quickly websites load, how apps respond, and how infrastructure handles repeated demand.

What affects the outcome

Caching matters because it is one of the most common ways to improve performance and reduce repeated work.

It affects how quickly websites load, how apps respond, and how infrastructure handles repeated demand.

A common misconception is that caching always shows the newest data. In reality, caches can serve older data until they refresh or are invalidated.

Another misconception is that caching only matters for huge platforms. Smaller sites and apps benefit too.

Where people run into it

A common misconception is that caching always shows the newest data. In reality, caches can serve older data until they refresh or are invalidated.

Another misconception is that caching only matters for huge platforms. Smaller sites and apps benefit too.

Related questions

What to learn next

Sources

• Cloudflare Caching Learning Center
• MDN HTTP Caching