CDN

What is CDN?

CDN stands for Content Delivery Network and is a geographically distributed network of servers that stores a copy (cache) of static content such as images, CSS, and JavaScript. When a user visits your page, the files are delivered from the server closest to them — called an edge server — instead of from one central location. This shortens the distance the data has to travel and produces faster response times.

Why does CDN matter?

Speed is directly tied to conversion and rankings. By serving files from a server near the customer, a CDN reduces latency and improves load times — including Core Web Vitals such as LCP (Largest Contentful Paint). A CDN also offloads the origin server during traffic spikes (like Black Friday) and provides a layer of DDoS protection, keeping the store available and stable.

Common use cases

• Product images and theme assets delivered from edge servers instead of a single origin server.
• Traffic spikes during campaigns and sales, when many concurrent visitors must be handled.
• International selling, where customers in different countries need the same low response time.
• Image optimization, where the CDN converts to modern formats like WebP and adjusts the size.

Shopify perspective

Every Shopify store delivers content through a built-in, managed CDN that you can neither turn off nor replace. Files you upload — product images and theme files — are served automatically from cdn.shopify.com and cached globally. Shopify also converts images to modern formats and supports dynamic resizing via URL parameters. So you don’t need to set up your own CDN, but you should still compress images before upload, because the CDN only delivers the files fast — it doesn’t make them smaller for you.