Cython is not only a very fast and comfortable way to talk to native code and libraries, it is also a widely used tool for speeding up Python code. The Cython compiler translates Python code to C or C++ code, and applies many static optimisations that make Python code run visibly faster than in the interpreter. But even better, it supports static type annotations that allow direct use of C/C++ data types and functions, which the compiler uses to convert and optimise the code into fast, native C. The tight integration of all three languages, Python, C and C++, makes it possible to freely mix Python features like generators and comprehensions with C/C++ features like native data types, pointer arithmetic or manually tuned memory management in the same code. This talk by a core developer introduces the Cython compiler by interactive code examples, and shows how you can use it to speed up your Python code. You will learn how you can profile a Python module and use Cython to compile and optimise it into a fast binary extension module. All of that, without losing the ability to run it through common development tools like static analysers or coverage test tools.