What is a CDN, and do you need one?

A content delivery network (CDN) keeps copies of your static files, such as images, styles and scripts, on servers around the world and serves each visitor from a nearby one. It helps sites with a distant or international audience and heavy files; a small local site may not need one.

By Nazar Kashuba · Reviewed

Distance matters to speed. A visitor far from your server waits longer. A CDN reduces that by serving copies from many locations.

What it does

  • Speeds up delivery of static files to visitors around the world.
  • Reduces load on your own server.
  • Often adds protection against some kinds of traffic floods and basic filtering.
  • Can handle encryption certificates and compression.

When it helps most

  • Your visitors are spread across countries.
  • Pages carry large images or media.
  • You expect sudden spikes of traffic.

When you may not need one

  • A small site whose visitors are mostly near your server.
  • Pages that are light and cached well by the browser already.
  • Your hosting already includes edge delivery.

Things to consider

  1. A CDN adds another party that sees your visitors’ traffic, which matters for privacy information.
  2. Cache settings must be right, or visitors see old content.
  3. Version your file names so that changes appear at once.

Start by fixing what is heavy: oversized images and unneeded scripts. A CDN accelerates a lean site; it does not rescue a bloated one.

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