Explore how to build and distribute large-scale desktop applications using Python in this 45-minute talk from the EuroPython 2019 conference. Discover best practices for maximizing security, improving performance, and ensuring stability when shipping Python code to hundreds of millions of devices. Learn from Dropbox's decade-long experience in developing cross-platform apps for Windows, macOS, and Linux. Gain insights into key decisions such as migrating to Python 3, using HTML for GUI development, and integrating other programming languages like Rust. Uncover valuable tools and libraries that can help scale your development process from a small team to over 100 engineers. Whether you're a Python enthusiast or a developer looking to create desktop applications, this talk provides practical knowledge to inspire and guide your future projects.