How I automated dead endpoint detection and removed 16,000 lines from our Node.js codebase

Eight years of product iterations leaves marks. Our Express API had grown to 45,000 lines of code across hundreds of endpoints — features that shipped, features that didn't, integrations that were replaced, experiments that were abandoned. Nobody knew exactly what was still being used. Static analysis wasn't the answer. Tools like ESLint can tell you what's unreachable at the code level, but they can't tell you whether an endpoint is receiving live traffic. An endpoint can be perfectly reachable