Circuit Breaker Pattern

In a microservices architecture, services depend on other services to complete their work. For example, an Order Service might call the Payment Service, Inventory Service, and Notification Service when a customer places an order. Under normal conditions, these calls work as expected.

But what happens when the Payment Service becomes unavailable? If the Order Service continues sending requests to it, those requests may repeatedly fail or time out. Each failed request wastes time and consumes resources such as connections, memory, and concurrency slots.

As more requests arrive, the Order Service itself might become overloaded. This is how a failure in one service can spread to other services and eventually affect the entire application.

The Circuit Breaker Pattern helps prevent this problem. Instead of continuously calling an unhealthy dependency, a circuit breaker detects repeated failures and temporarily stops sending requests to it.

This allows the failing service time to recover while protecting the calling service from unnecessary work. Let's understand how it works.