A variable is an element of a dynamic computing process. The decision engine computes the results of variables based on input parameters by using specific computing logic. The decision engine supports various variable types. The decision engine can compute the results of variables by using functions, scenario recognition models, or velocity metrics. For example, the decision engine can use a function that extracts the suffix of email addresses, an Account Abuse Detection Pro model, or a metric that indicates the number of accounts associated with an IP address in an hour to compute the results of variables. This topic describes how to manage variables.