Instagram employs Python in one of the world's largest settings, using it to serve 1 billion monthly active users. We chose Python because of its reputation for simplicity and practicality, which aligns well with our philosophy of “do the simple thing first.” Come learn about the challenges, learnings, and techniques used at Instagram to maintain and advance our million-LOC, thousand endpoint Django application. We will discuss how we empower engineers to build quickly while managing complexity and maintaining a high-quality codebase. Topics may include AST-based lint frameworks, tools for large-scale codebase refactors, adopting Python type annotations, types for Django HTTP APIs, safe hot-reloading of Python code, and more. This will be an informal setting; if you've ever wondered how Python works at scale, this is your chance to ask!