Circuit Breaker Pattern Explained: How It Prevents Cascading Failures in Apps

The Circuit Breaker pattern is a software resilience technique that stops an application from repeatedly calling a failing or unresponsive service. Without it, failed requests can pile up, exhaust connection pools and worker threads, and cause a cascading failure that brings down multiple services. The pattern works by monitoring service health and switching between three states — Closed (normal operation), Open (requests blocked), and Half-Open (recovery testing). It is especially critical in microservices architectures, where a single dependency like a payment or authentication service going down can destabilize an entire application. By cutting off calls to an unhealthy service early, the circuit breaker gives it time to recover while keeping the rest of the system responsive.