A CDN (Content Delivery Network) is a distributed infrastructure of servers spread geographically across the globe. Its purpose: to bring your static assets — images, CSS, JavaScript, videos — closer to the visitor requesting them, in order to reduce latency and dramatically speed up page loading. For e-commerce stores, the CDN has become an indispensable SEO lever since Google incorporated page speed as a ranking factor.
What exactly is a CDN?
A CDN consists of a network of servers called "edge nodes" (or Points of Presence, PoP). When a visitor loads your store from London, Manchester, or Birmingham, their request is automatically routed to the nearest CDN node — rather than to your main hosting server, which might be located in Germany, the United States, or anywhere else in the world. The file is served from a few miles away instead of thousands: the latency gain is immediate and measurable.
In practical terms, here is what happens without a CDN: your visitor sends an HTTP request to your hosting server, waits for the server to locate the file, read it from disk, and transmit it over the internet. With a CDN, the resource is already cached on a geographically nearby server: the response arrives in tens of milliseconds instead of hundreds. For product images — typically the heaviest files on an e-commerce page — this difference is dramatic.
Why a CDN is an SEO factor for e-commerce
Since Google's Page Experience update (2021), page load speed has been officially incorporated into the ranking algorithm via the Core Web Vitals. Among these metrics, LCP (Largest Contentful Paint) measures the time for the largest visible element to render — in 80% of e-commerce pages, that element is the main product image or the hero banner. An LCP below 2.5 seconds is considered "good" by Google; beyond 4 seconds, Google penalises the page in search results.
A well-configured CDN can bring your LCP from 4–5 seconds down to under 1.5 seconds on images. This is one of the most significant gains achievable without a full site overhaul. Moreover, by reducing the load on your origin server, the CDN improves the stability and availability of your store during traffic peaks (sales events, Black Friday), avoiding 503 errors that hurt Google's crawl.
LCP and product images
CDN and image optimisation: two problems solved at once
Modern CDNs no longer simply distribute existing files: they include on-the-fly image transformation capabilities. In practice, this means that the JPEG image you uploaded to your server can be automatically converted to WebP or AVIF based on the visitor's browser, resized according to screen size, and compressed without any visible loss of quality.
An 800 KB JPEG becomes a 250 KB WebP or a 150 KB AVIF — without you having to do anything manually. Across a store with 500, 2,000 or 10,000 product references, the bandwidth savings are considerable, and the impact on load time is direct.
Global distribution
Edge nodes serve your images from the point closest to the visitor, reducing latency to just tens of milliseconds.
Automatic conversion
On-the-fly conversion to WebP and AVIF based on the visitor's browser, with no manual action required.
Long-term caching
Resources are cached for 1 year on edge nodes, eliminating repeated requests to your origin server.
Cloudflare R2: the CDN technology behind Lexiik
Lexiik relies on Cloudflare R2 and Cloudflare's global network to serve your product images. Cloudflare operates more than 300 Points of Presence (PoP) across more than 100 countries, making it one of the most extensive CDN networks in the world. In the UK, nodes are present in London, Manchester, and other major cities: the latency for a UK visitor is typically under 20 milliseconds.
Cloudflare R2 is an S3-compatible object storage solution with no egress bandwidth fees. Unlike AWS S3 or Google Cloud Storage, which charge for every gigabyte transferred to end users, R2 charges only for storage and operations. For high-traffic e-commerce stores with large image catalogues, this architecture keeps costs predictable regardless of audience size.
From a privacy standpoint, Cloudflare commits to not analysing or monetising data passing through its network. Your product images are not used for machine learning or targeted advertising. They are stored and distributed — nothing more.
How the Lexiik CDN works in practice
Lexiik's architecture is based on what is known as "cache-through": your images remain on your origin PrestaShop server, but when a visitor first lands on a product page, Lexiik intercepts the image request, fetches it from your server, stores it on Cloudflare R2, and then serves it from the CDN for all subsequent visits.
- The PrestaShop module automatically installs an override of the Link class, which redirects image URLs to cdn.lexiik.com
- On the first visit to a page, if the image is not yet on the CDN, Lexiik fetches it from your server and uploads it to Cloudflare R2
- The image is stored with a Cache-Control header of 1 year (max-age=31536000) on Cloudflare edge nodes
- All subsequent visits receive the image directly from the nearest CDN node, without ever hitting your origin server
- If you update an image in your PrestaShop back office, Lexiik automatically invalidates the CDN cache for that specific image
This approach offers a major advantage for merchants: zero manual configuration. There is no need to modify DNS settings, configure an S3 bucket, manage Cloudflare API keys, or edit templates. Installing the module is all it takes.
CDN vs traditional hosting: a latency comparison
To illustrate the concrete impact of a CDN, here are the typical figures observed on PrestaShop stores hosted on shared or VPS servers in Europe:
- 500 KB JPEG image without CDN (server in Germany → visitor in London): 400–800 ms Time To First Byte + transfer
- Same image as WebP via Lexiik CDN (edge in London → visitor in London): 15–40 ms Time To First Byte
- Typical LCP without CDN on a product page: 3.5 to 6 seconds
- Typical LCP with Lexiik CDN on the same page: 0.8 to 1.8 seconds
- Average Google PageSpeed Insights score without CDN: 45–60 (mobile)
- Average Google PageSpeed Insights score with Lexiik CDN: 75–90 (mobile)
Zero configuration, one-click setup
The Lexiik approach: CDN without configuration or technical expertise
Setting up a professional-grade CDN typically requires advanced technical skills: DNS configuration, SSL certificate management, cache rule settings, integration with the e-commerce platform, and more. Lexiik automates this entire process for PrestaShop.
The module installs an override of PrestaShop's Link class — the CMS's native mechanism for customising core behaviour without modifying the original files. This override intercepts image URL generation and transparently redirects them to the CDN. From the perspective of your theme and templates, nothing changes: images are still called via the standard PrestaShop functions, but they are served from Cloudflare's global network.