Edge Services

 Any Service which is located close to user and which actually reduces latency by providing   CDN services, API Gateway, DDOS Prevention(Rate Limiting) - They are collectively called EDGE Services 

CDN  - Content Delivery Network

Throttle - DDOS Prevention

API Gateway 

Filtering 

Authentication

Logging

https://medium.com/knerd/api-infrastructure-at-knewton-whats-in-an-edge-service-51a3777aeb41