The "Double-Booking" Nightmare: Building a Rule-Driven Hostel Allocator with MongoDB Transactions

How I built a transactional hostel allocation engine that eliminates race conditions and double-bookings using MongoDB sessions. Handling logistics for a 500+ person event—like a major hackathon or campus festival—is easy on paper. It becomes significantly harder at 2:00 AM when multiple exhausted teams arrive at the registration desk simultaneously while operators manually juggle room assignments. In this article, I’m pulling back the curtain on the "brain" of Project Morpheus : a transactional