The disclosure relates to technology for coordinating execution of serverless functions. One or more events are received from one or more external sources. The one or more events are mapped to one or more event states of a processing graph according to mapping rules, the one or more event states including one or more actions, and the one or more actions are executed in response to the one or more events satisfying conditions of the mapping rules. An event response is the received in reply to the received one or more events, where the event response is based on execution of one or more tasks corresponding to a sequence of the executed one or more actions.