PADRONE is new platform for dynamic binary analysis and optimization. It provides an API to help clients design and develop analysis and optimization tools for binary executables. PADRONE attaches to running applications, only needing the executable binary in memory. No source code or debug information is needed. No application restart is needed either. This is specially interesting for legacy or commercial applications, but also in the context of cloud deployment, where actual hardware is unknown, and other applications competing for hardware resources can vary. We describe the infrastructure of PADRONE, and show that its profiling overhead is minimal. We illustrate its use through two examples. In the first one, we show how we measure the performance of the hotpot of benchmark. In the second one, we replace the hotspot of a function by an optimized version, while the program runs. We believe PADRONE fits an empty design point in the ecosystem of dynamic binary tools.