A CDN (content delivery network) stores copies of your files on servers spread around the world.

The benefit

Visitors download the files from the server that is geographically closest to them: loading is faster, especially for an international audience.

When to use one

Useful as soon as you have visitors far from your host, or a lot of images. Services such as Cloudflare offer a free plan.

Key takeaway: a CDN shortens the distance between your files and your visitors.