Abstract: Embodiments of the disclosure can include MapReduce systems and methods with integral mapper and reducer compute runtime environments. An example system with an integral reducer compute runtime environment can include mappers and reducers executable on a computer cluster. The mappers can be operable to receive raw input data and generate first input data based on the raw input data. The mappers can be operable to generate first result data based on the first input data. Based on the first result data, the mappers can be operable to generate (K, V) pairs. The reducers can be operable to receive the (K, V) pairs and generate second input data based on the (K, V) pairs. The reducers can be operable to transmit the second input data to integral compute runtime environment being run within the reducers and operable to generate second result data based on the second input data. Based on the second result data, the reducers can be operable to generate output data.