Pull vs Push CDN

By Pradyumna Chippigiri

January 26, 2026

Today I learned the difference between pull CDNs (fetch on demand) and push CDNs (preload ahead of traffic).

Pull CDN (standard):

• User requests image.jpg
• CDN doesn’t have it → fetches from origin
• CDN caches it and sends it, ad the same cached asset is used for the next request
• Low maintenance, works well for frequently changing content (unpredictable).

Push CDN:

• You upload content to the CDN before anyone requests it
• High control, useful when you can predict demand
• Great for hot, predictable content in fixed regions

Netflix is a classic push example:

• it preloads popular movies/series to edge servers during off‑peak hours so playback is instant when users wake up.
• Netflix runs its own CDN called Open Connect, with Open Connect Appliances (OCAs) deployed inside/at the edge of ISP networks and at interconnect locations.

Cache invalidation differences:

• Pull CDN: usually relies on TTLs or purge APIs; updates propagate after expiry or manual purge.
• Push CDN: you must explicitly update or purge cached assets when content changes, because the CDN won’t refetch on its own.

Example

Pull: Request → CDN miss → Origin → CDN cache → Next request hits edge
Push: Upload to CDN → Edge caches → First request served from edge

To read more about it:

• Netflix Open Connect (CDN architecture)