A new approach is proposed that contemplates systems and methods to support streaming aggregation for analysis of electronic transactions. First, a plurality of metrics to be measured/analyzed for a stream of real life events, such as processing steps of the electronic transactions are defined and converted to one or more generic metrics for aggregation. In some embodiments, the plurality of metrics flexibly include ad-hoc aggregation measures as well as various user-defined functions (UDFs), which allow a user/processor/evaluator of the electronic transactions to define and collect various types of information of the electronic transactions for analysis. Once converted, the generic metrics of the stream of real life events are aggregated by an aggregation engine in real time. The aggregation results are then saved in an aggregation database, which is queried by the user for real time analysis of the electronic transaction.