How can I outsource performance critical stuff to C++? Is there an example?
If you're talking about Flex on AIR platform (basically out of browser application), there's a way to interact with native code on the same machine. You may want to check this out (official doc from Adobe) : http://www.adobe.com/devnet/air/ajax/quickstart/interacting_with_native_process_print.html
If you're talking about flex in the browser, then I would agree with Dmitry, you can use many different things: - Web Services - HTTP Request/Response - RPC calls - Or even make your own real-time socket (in some cases can be the most performant way to do this) Now, that would require a C++ Server, listening to those calls, doing the stuff and then replying. => Meaning you need networking.