# Edge-side includes

> A caching technique where the edge stores the shared part of a page and assembles only the personal fragments for each user, so a logged-in page can still be served mostly from cache.

Performance

## In Quorum

Edge-side includes research adds 20 points to a CDN’s `page` hit ratio, from 70% to 90% (10), because the edge caches the shell of a logged-in page. The TTL still multiplies it, and the hit ratio still caps at 95%.

## Design

[CDN](https://wiki.playquorum.dev/design/05-components.md#cdn)

## Read next

[CDN (content delivery network)](https://wiki.playquorum.dev/glossary/cdn-content-delivery-network.md), [Cache hit rate](https://wiki.playquorum.dev/glossary/cache-hit-rate.md), [Tiered caching](https://wiki.playquorum.dev/glossary/tiered-caching.md), [Egress](https://wiki.playquorum.dev/glossary/egress.md)

## Learn more

- [Fastly docs: Edge Side Includes](https://www.fastly.com/documentation/reference/vcl/statements/esi/)

## See also

- [Glossary](https://wiki.playquorum.dev/glossary.md)

Source: https://wiki.playquorum.dev/glossary/edge-side-includes