What is a CDN, and do I need one for offloaded media?

A CDN, or content delivery network, keeps copies of your files on servers around the world and answers each visitor from a nearby one. You don't need one to offload media, because your bucket can serve files by itself. It helps most when your visitors are far from your bucket's region.

How it differs from storage

A bucket stores the original files in one region. A CDN sits in front of it and caches copies. When a visitor asks for an image, the CDN answers from its cache if it can, and fetches it from the bucket if it can't.

When it's worth it

• Your visitors are spread across the world.
• Your site sends a lot of traffic, and your provider charges for downloads.
• You want your media on your own domain, and your provider needs a CDN for that.

If most visitors are near one region, a bucket in that region may be enough.

Some providers include one

Some storage comes with a CDN, or with a way to connect one at little cost. The storage comparison shows what each offers.

How Offloft handles this

Offloft works with or without a CDN: set your address in Settings → Delivery, and the delivery check tests it. Changed files get a new address, so the CDN can't keep showing an old version.