Abstract: An online monitoring method and system (10) is disclosed. The system comprises a process data connection device (20) for the acquisition of a first set of process data (30) coming from a process data source (40), an input system (50) for the creation of a process fingerprint (60), a storage device (70) for storing the created process fingerprint (60), a data processing device (80) for calculating the distance between the stored process fingerprint (60) and the new sets of process data (30), a management device (75) for managing which fingerprints need to be evaluated and a feedback device (77) which handles the actions that need to be performed based on detection such as displaying the distance (90) on an output device (100).