Content delivery and a CDN: getting the file close to the viewer
A content delivery network keeps copies of your files in data centres near your users, so a request is answered from the nearest one instead of travelling to your server every time.
What is a content delivery network?
A CDN sits in front of your origin: an object store, a load balancer or an API. A request lands at the closest edge location. If that location already holds a fresh copy of the file, it answers in a few milliseconds and your origin never hears about the request at all.
What you actually configure is the cache: how long a copy stays valid, what counts as the same request, and how you throw a copy away when the file changes. For a video that never changes again, a long cache is free speed. For a download that should expire, the cache rules carry your access rules with them, which is why signed URLs are part of the CDN and not of your application.
Five ways to run it
Each of the big clouds sells it as a managed service, and you can also run the caching layer yourself. Same job, a different bill and a different console.
Amazon CloudFront[1]
The CDN on AWS. It pulls from S3, from a load balancer or from any origin you name, ends the TLS connection at the edge, and signs URLs or cookies when a file should only be readable for a while.
Official documentation →Azure Front Door[2]
Microsoft's edge platform. Caching, global load balancing and a web application firewall live in one profile, so routing and protection are configured in the same place as the cache.
Official documentation →Cloud CDN and Media CDN[3]
Cloud CDN caches in front of a Google Cloud load balancer. Media CDN is the separate product for video at large scale, on the network YouTube uses.
Official documentation →Cloudflare or Fastly[4]
A CDN that does not belong to the cloud your application runs in. That is the point of it: you can move the workload later without moving the domain, the certificates and the cache rules.
Product documentation →Nginx or Varnish[5]
A caching reverse proxy on machines you operate. It is the right answer when the files may not leave your building, and the wrong one when your users are spread across continents.
Project documentation →Where I used it
The video pipeline
The finished clips sit in object storage and are served through CloudFront. The share links are signed, so a link that was handed out for one review stops working on its own instead of living forever.
Read the write-up →Managed and self-hosted together: hybrid
A CDN is a copy of your file on somebody else's machine, in a country you did not pick. That is the hybrid question here, and it is a different one from where your application runs. The usual split: public assets go to the edge, anything with a name or a case number in it stays behind your own cache and is served from one place, slower and on purpose.
What would help you next?
Learn to decide
The course “From Managed to Hybrid” teaches where AI should run: what each layer costs, what you operate and where your data has to stay. It is in preparation, with a free live session first.
Linda MohamedAI and cloud consultant, AWS Community Hero, Vienna
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Read more on ai-solutions.wiki
My open knowledge base, with longer comparisons, pricing notes and sources.
Sources
- Amazon CloudFront documentation. https://docs.aws.amazon.com/AmazonCloudFront/latest/DeveloperGuide/Introduction.html
- Azure Front Door documentation. https://learn.microsoft.com/en-us/azure/frontdoor/front-door-overview
- Cloud CDN and Media CDN documentation. https://cloud.google.com/cdn/docs/overview
- Cloudflare cache documentation. https://developers.cloudflare.com/cache/
- Varnish Cache documentation. https://varnish-cache.org/docs/
- CDN, what it is, ai-solutions.wiki. https://ai-solutions.wiki/glossary/cdn/
- Caching, the basics, ai-solutions.wiki. https://ai-solutions.wiki/basics/what-is-caching/
- Google Media CDN, ai-solutions.wiki. https://ai-solutions.wiki/tools/google-media-cdn/
Links checked October 2026. Product names and features change: check the linked pages before you decide.
