# CDN: definition

> A CDN, or content delivery network, is a set of geographically distributed servers that serve a site's static files from the point closest to the visitor.

- Source canonique : [https://allaux.fr/en/glossaire/cdn](https://allaux.fr/en/glossaire/cdn)
- Langue : EN
- Dernière mise à jour : 2026-09-30

## What a CDN actually changes

Without a CDN, every visitor receives a shop's images, stylesheets and scripts from a single server, often located in one particular country. A distant visitor faces a longer network round trip before their browser even starts displaying the page. A CDN copies these static files onto servers spread across the world, and routes each visitor to the copy closest to them.

For a PrestaShop or WooCommerce shop, the effect shows up mainly on product images and the theme's CSS and JavaScript files. These files rarely change, which makes them ideal to distribute via a CDN, unlike dynamically generated pages (cart, customer account) which stay served by the origin server.

A CDN doesn't replace decent hosting or a well-tuned application cache: it reduces the transport latency of static files, without speeding up the calculations done server-side.

## FAQ

### Is a CDN useful for a shop that only sells in one country?

The effect is more limited if the server is already close to visitors, but a CDN still helps absorb traffic spikes.

### Does the CDN affect SEO?

Indirectly yes, because it improves loading time, a factor Google takes into account through Core Web Vitals.

### Does PrestaShop or WooCommerce need a specific CDN?

No, a general-purpose CDN works for both: it's just a matter of configuring the right domain or plugin.