CDNs & Caching
Serving fast from an edge near the visitor.
CDNs & Caching is taught here in 3 lessons, running from How a CDN serves your content through to Invalidation, purging and what not to cache. Each lesson takes one topic, shows the working code, and links onward to the next, so the course can be read straight through in order.
| Track | Building a Website |
| Lessons | 3 |
| Level | Beginner |
| Reading time | about 39 minutes |
| Prerequisites | Helpful, but not required: Web Hosting |
Lessons
- How a CDN serves your contentEdge locations, cache hits and misses, origin shielding, and how to tell which layer answered a request.
- Cache headers and cache keysThe headers that decide how long the edge holds a copy, and what makes two requests share one entry.
- Invalidation, purging and what not to cacheHow to retire a cached copy quickly, why fingerprinted URLs beat purging, and the responses that must never be stored.
More in Building a Website
SEO Basics Domains & DNS Web Hosting Accessibility
FAQ
How long does the CDNs & Caching course take?
It has 3 lessons, about 39 minutes of reading. Expect roughly twice that if you type out and run every example.
Do I need prior experience for CDNs & Caching?
Not strictly. It helps to have read Web Hosting first, because some lessons build on it, but every lesson explains its own assumptions.
What should I read after CDNs & Caching?
Continue with Accessibility (3 lessons), the next course in Building a Website.
Last refreshed 2026-09-18.