Load balancing
Spread traffic across multiple backends automatically. See our detailed overview of load balancing on Fastly.
Two mechanisms exist for configuring load balancing of Fastly services via the API. Directors are bound to a VCL service version and are a good choice if you want to set up load balancing as part of your version-locked service configuration, but you require more than one director group. (If you only need to put all backends under a single director consider the auto_loadbalance property of a Backend.)
Conversely, dynamic server pools are designed to create a load balancing container attached to your service, but with the actual servers defined dynamically. Using a dynamic server pool, servers can be added and removed without creating and activating a new version of the service.