Single instance cannot scale beyond limited load threshold

No matter how optimized the app is, a single instance can handle only a limited amount of load and traffic. Beyond this threshold, response times degrade and requests may be dropped.

Run multiple instances of the app and distribute traffic via a load balancer (Nginx or HAProxy). For multi-core systems, use clustering to run one instance per CPU core. Configure session affinity (sticky sessions) or use Redis for session data to handle stateful requests across instances.