JavaScript runs at near-C speed despite being 'interpreted.' The JVM does the same. PyPy is 5-10x faster than CPython. The trick is JIT compilation -- the runtime watches what your code actually does and rewrites the hot paths to native machine code. Knowing how it works explains why your benchmarks are wrong, why warm-up matters, and why some optimizations help and others hurt.
Engineering Craft
TypeScript, CI/CD, databases, observability -- the skills that make code production-ready.
