The document summarizes different types of splitters that can be used to split messages and process them in parallel in Mule flows. It describes collection splitters that split collections, message chunk splitters that split messages into fixed-size chunks, and scatter-gather splitters that send a single message to multiple endpoints concurrently. It provides examples of splitting payloads into lists or byte arrays and aggregating the results after parallel processing. Split messages may be resequenced before aggregation to reconstruct the original order.