A phase defines a stage in the life of a request where you can execute rulesets. Phases are defined by Cloudflare and cannot be modified.
Phases exist at two levels: at the account level and at the zone level. For the same phase, rules defined at the account level are evaluated before the rules defined at the zone level.
The following diagram outlines the request handling process where requests go through the available phases:
Cloudflare products are specific to one or more phases, and they add support for different features. Check the documentation for each Cloudflare product for details on the applicable phases.
Phase entry point ruleset
Phases have an entry point at the account and zone levels. An entry point ruleset contains a list of ordered rules that run in the phase. You can define rules in an entry point ruleset that execute a different ruleset.