What is backpressure handling in Spring WebFlux and why is it critical?

Backpressure controls the rate at which producers emit data to prevent consumer overload.

In reactive systems, producers may generate data faster than consumers can process. Backpressure allows consumers to signal demand. WebFlux uses Project Reactor operators like limitRate, buffer, and onBackpressureBuffer to manage flow. Without it, systems risk memory overload and latency spikes.