A message processing system that provides a processing flow, the message processing system comprising an input message consumer configured to consume input messages from an input message queue, where the input messages comprise priority information. The message processing system includes a command producer configured to produce commands for a next step in the processing flow. Each command produced may include a target time determined using priority information extracted from an input message to which that command corresponds. The message processing system comprises a queue for commands. The message processing system further comprises a command consumer configured to select commands that have expired target times from the command queue for processing and consume the selected commands from the command queue.