Why Python Told Me To Stop Writing My Own Code

April 2026 · 6 min read* A .NET developer's guide to Python performance — and why the rules are different I've spent most of my career in .NET. C#, the CLR, JIT compilation — these are things I know deeply. I'm proficient in TypeScript and JavaScript for full-stack and mobile work. Python, though, has always been at arm's length. I never really needed to delve into that very popular ecosystem. That changed recently. And the first real thing it taught me was something I hadn't expected: don't write your own raw code if you can help it. That's strange advice if you're coming from C#. In .NET, hand-crafted code and library code run through the same JIT compiler. Performance is often comparable, so you usually optimise based on other considerations — readability, semantics, maintainability. Python, it turns out, works very differently. Understanding why changes how you write it. How Python Actually Runs The version of Python most people use is CPython — the reference implementation, writte