What is prefetching?

Prefetching is the predictive loading of resources that users are likely to need soon. A browser can prepare DNS lookups, connections, scripts, stylesheets or even future pages so that later navigation feels faster.

The term is used for several techniques. MDN explains modern variants in the context of speculative loading.

Which types of prefetching exist?

Common variants include:

• dns-prefetch: resolves the domain of an external host early
• preconnect: also opens an early connection
• prefetch: loads a resource for likely later use
• preload: prioritizes a resource needed for the current page
• Speculation Rules: enable modern preloading or prerendering of future pages

These terms are often confused. preload is usually about critical resources for the current page, while prefetch points to possible later use.

When is prefetching useful?

Prefetching can be useful when the next step is very likely. Examples include multi-step forms, checkout flows, app-like interfaces or pages where users almost always move to the same next section.

For regular websites, prefetching should be selective. Too much predictive loading can waste bandwidth, create server load and raise privacy questions when third-party services are involved. This is especially relevant alongside Consent Mode and consent management.

Prefetching and performance

In performance optimization, prefetching is not evaluated in isolation. The question is whether it measurably helps. Sometimes image sizing, caching, critical CSS or reducing JavaScript creates a bigger improvement.

Prefetching is a tool for targeted speed gains, not a default best practice for every page. It should be tested together with Core Web Vitals and real user journeys.