Fix MERN API Bugs

My production MERN app is throwing backend issues that I need resolved quickly. The most critical problems sit in the Node + Express layer: API endpoint failures and intermittent server errors, with the user-authentication route being the main culprit. What I need you to do • Trace the failing auth flow, locate the root cause (token handling, middleware, DB calls, etc.) and patch it. • Audit the rest of the backend for similar API glitches, cleaning up code where necessary. • Make sure every fix plays nicely with MongoDB queries and indexes. Please keep the code clean, well-commented, and push via Git so I can review commits. I’m aiming for a 3- to 5-day turnaround. The budget is set at roughly €20, but I’m flexible if unexpected complexity pops up—as long as the fixes are solid and delivered fast. If this sounds like a straightforward task for you, let’s get started.

Projektin tunnus (ID): 40225817