Personalization is a semi-custom process for Stream. We assign a data scientist to your account to understand your use case, pick the best base model(s), and then train and deploy the model(s). The data scientist stays connected to your account with 2 week check-ins to ensure the model is still performing as needed (tweaking things to stay optimal).
Because of this process, we don't have a way for you to test personalization. Please contact us if you would like to discuss your personalization use case and determine if Stream is a good fit.