Essentials

Essentials is a collection of guides that introduce you to core concepts essential to understanding content delivery networks (CDNs) and Fastly.

What is an API?

An application programming interface (API) facilitates communication between technology products and systems. It is sometimes said that APIs…

What is caching?

A cache is a location that temporarily stores data for faster retrieval by the things that need to access it. Caching refers to the process of storing this data.

What is a CDN?

A content delivery network, or CDN, is a network of servers distributed all across the world that work together to make delivering content…

What is image optimization?

Image optimization refers to the process of creating and delivering high-quality images in the right format, dimension, and resolution for…

What is purging?

Cache invalidation, otherwise known as purging or cache purge, is the process of eliminating content from cache ahead of when it would naturally expire or be evicted. Once content is purged, a request for that content will be retrieved from the source rather than the cache.