Methods, systems, and apparatus, including computer programs encoded on computer storage media, for executing the operations represented by an asynchronous execution graph. One of the methods includes receiving data characterizing an asynchronous execution graph comprising one or more subgraphs, wherein each subgraph comprises a plurality of nodes connected by edges, the plurality of nodes comprising a source node, one or more processor nodes, and one or more sink nodes; receiving source data from an external system that corresponds to the source node of a first subgraph in the graph; in response, executing the operations represented by the processor nodes in the first subgraph; and executing the operations represented by each sink node in the first subgraph.