The normal state of the circuit breaker pattern is the closed state, which indicates that all services are up and running. It will pass all requests through to the services. If the number of failure requests increases by a predefined threshold, this will turn to the open state:

As you can see from the preceding diagram, the Client is trying to access the service, and the request is passed through the Circuit breaker. In this case, our backend microservice (referred to as the Supplier Microservice) is up and running, so it can respond without latency. The Circuit breaker passes that request through to the Client.