Custom load balancing rules let you customize the behavior of your load balancer based on the characteristics of a request.
For example, you could create a rule that selects an origin pool based on the URI path of an HTTP request.
How custom rules work
As with WAF custom rules, each load balancing custom rule is a combination of two elements: an expression and an action. Expressions define the criteria for an HTTP request to trigger an action. The action tells Cloudflare how to handle the request.
You can create Load Balancing rules whenever you create or edit a load balancer in Traffic > Load Balancing.
When building expressions for Load Balancing rules, refer to Supported fields and operators for definitions and usage.
By default, non-Enterprise customers have one Load Balancing rule per load balancer hostname. For more rules, upgrade to Enterprise.
At the moment, you cannot use Load Balancing rules with Cloudflare Spectrum.