Abstract: Provided is a system for testing a machine learning (ML) model based on simulations in an offline environment that includes at least one processor programmed or configured to receive historical transaction data, generate online simulation data, wherein generating the online simulation data includes modifying the historical timestamp of each data record to provide online simulation data. The processor is further programmed or configured to determine a timeline for a plurality of data insertion actions and a plurality of data request actions based on the online simulation data, perform a simulation of online activities involving a stateful ML model using the timeline for the plurality of data insertion actions and the plurality of data request actions, and validate the stateful ML model based on the simulation of online activities. Methods and computer program products are also provided.