Do CDN prefetch user's static data or it's done on the request?

Question

As per Akamai -

A content delivery network (CDN) is a group of geographically distributed servers that speed up the delivery of web content by bringing it closer to where users are. Data centers across the globe use caching, a process that temporarily stores copies of files, so that you can access internet content from a web-enabled device or browser more quickly through a server near you. CDNs cache content like web pages, images, and video in proxy servers near to your physical location. This allows you to do things like watch a movie, download software, check your bank balance, post on social media, or make purchases, without having to wait for content to load.

So I am mainly interested in "post on social media"

Will the CDN prefetch a user's social media content (static?) or will it be done at the user's request because prefetching can be costly, complex and wasteful?

Prefetching generic static information, such as a website's landing page image, a viral video, product images (amazon must use CDN to deliver images for their products else it will take lot of time to load images and will be a very bad experience) makes sense.

Answer 1

Whether it is social media content or a static website, content is not fetched by Akamai except when a request comes to the platform for the content. At that point, depending on how the platform is configured for your particular site, the content is cached for later users for a period of time.

A few notes:

1. Akamai can be configured to automatically request the additional content linked on the page without waiting for the end user's browser to issue the request. Details: https://techdocs.akamai.com/property-mgr/docs/prefetching
2. You can use prefetching for both cacheable and non-cacheable objects. Details: https://techdocs.akamai.com/property-mgr/docs/prefetchable-objects
3. You can configure Akamai to prefresh that content as it nears the expiration of the caching time limit, checking to see if it has been modified. Details: https://techdocs.akamai.com/property-mgr/docs/cache-prefresh-refresh

Answer 2

In the case of user profiles, for example, I would not use caching. Synchronizing all the data to keep it up to date is complicated.

CDN systems usually let you set whether to cache the file and how often to update it.