Policy Simulator is a collection of endpoints for creating, running, and viewing a Replay. A `Replay` is a type of simulation that lets you see how your members' access to resources might change if you changed your IAM policy. During a `Replay`, Policy Simulator re-evaluates, or replays, past access attempts under both the current policy and your proposed policy, and compares those results to determine how your members' access might change under the proposed policy.
Note that we now highly recommend new customers to use Retail API, which incorporates the GA version of the Recommendations AI funtionalities. To enable Retail API, please visit https://console.cloud.google.com/apis/library/retail.googleapis.com. The Recommendations AI service enables customers to build end-to-end personalized recommendation systems without requiring a high level of expertise in machine learning, recommendation system, or Google Cloud.