Methods are provided for source-to-source transformations for graph processing on many-core platforms. A method includes receiving a graph application including one graph, expressed by a graph application programming interface configured for defining and manipulating graphs. The method further includes transforming, by a source-to-source compiler, the graph application into a plurality of parallel code variants. Each of the plurality of parallel code variants is specifically configured for parallel execution by a target one of a plurality of different many-core processors. The method also includes selecting and tuning, by a runtime component, a particular one of the parallel code variants for the parallel execution responsive to graph application characteristics, graph data, and an underlying code execution platform of the plurality of different many-core processors.