How I Built a Concurrency-Safe Reservation System

What happens when 100 users try to reserve the same seat at exactly the same time?

Without proper concurrency control, multiple users could end up booking the same seat—a classic race condition that every booking platform must solve.

To better understand how production reservation systems handle this problem, I built a Concurrency-Safe Movie Reservation Backend using FastAPI, PostgreSQL, Redis, and SQLAlchemy.

Rather than focusing on frontend features, my goal was to explore the backend engineering concepts that make reservation systems reliable under concurrent traffic.

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