Microservices-based application design has wrought in a subtle and smart change in the way software applications are being designed, deployed, and delivered. Applications now become a dynamic collection of services that rely on each other to perform various tasks. Highly complicated and sophisticated applications are bound to involve a large number of interdependent microservices. More dependencies mean more complications and complexities. This pattern acquires prominence because it contributes immensely for avoiding cascading service failure. The idea of the pattern is to continuously monitor the application's microservices and the traffic flowing among them in order to prevent failures. When failures do happen, this pattern comes handy in minimizing the impact of those failures on the application. This pattern also attempts to prevent failure in the first place. For some types of error conditions such as running out of memory, it is possible to recognize that failure is imminent and to take appropriate measures to prevent it.

This is typically accomplished by the service signaling that it is becoming unhealthy and the circuit breaker then gives the service a chance to recover by throttling back the number of requests or rerouting them completely. Once the service gets recovered, the circuit breaker slowly ramps up requests to the service so as not to immediately overwhelm it and risk it becoming unhealthy again.

For microservices, the circuit breaker pattern guarantees the bottom‑up resilience. If this pattern is implemented correctly, it can help in avoiding cascading failures by ensuring continuity of service even when services are unavailable. Precisely speaking, it is possible to build MSA applications that use this pattern to gracefully degrade functionality when a method call fails.