Circuit Breaker
In plain terms
A pattern that stops calling a failing service to prevent cascading failures.
Going deeper
Like an electrical breaker, it 'trips' after repeated failures, failing fast instead of hammering a struggling dependency, then periodically tests if it has recovered. It protects systems from collapse under partial outages.
Under the hood
Has closed, open, and half-open states; tuning thresholds and reset timeouts prevents both cascading failures and premature tripping.
Examples
Resilience4j, Hystrix (legacy), Polly (.NET), Istio outlier detection.
Think of it like...
Like a home fuse that cuts power when a circuit overloads, preventing the whole house from catching fire.