I Had No Idea Which Endpoint Was Slowest. So I Built My Own Metrics.

In Part 10 , I added structured logging and request IDs. I could now trace a single request through my entire backend — every log line tagged, searchable, debuggable in seconds. But I still couldn't answer basic questions: How many requests did /entries handle today? What's the average response time for /login ? Which endpoint is the slowest? Are errors increasing? I had detailed logs for individual requests but zero visibility into the system as a whole. That's like having a microscope but no d