What is CircuitBreaker?

A Circuit Breaker is a software design pattern that stops a program from repeatedly trying an operation that is failing, by “tripping” and temporarily blocking further calls. It then periodically checks if the operation has recovered before allowing traffic again.

Let's break it down

  • Circuit Breaker: Like an electrical breaker, it cuts off a flow-in this case, a flow of requests.
  • Design pattern: A reusable solution that developers apply to common problems.
  • Stops a program from repeatedly trying: Prevents the code from sending the same failing request over and over.
  • Operation that is failing: Any call that returns errors, such as a web service or database query.
  • “Tripping”: Switching to an “open” state where new calls are blocked.
  • Temporarily blocking further calls: Holds off new attempts for a short time.
  • Periodically checks if the operation has recovered: After a wait, it tries again in a “half-open” state to see if things are back to normal.

Why does it matter?

It keeps a system stable by preventing one broken component from dragging down the whole application, reduces wasted resources, and gives users a faster, more predictable response when something goes wrong.

Where is it used?

  • Microservice architectures where one service calls many others.
  • External API integrations, such as payment gateways or weather services.
  • Database connection pools that may become overloaded.
  • Cloud functions that rely on third-party storage or messaging services.

Good things about it

  • Protects healthy parts of the system from cascading failures.
  • Provides fast failure responses instead of long time-outs.
  • Automatically attempts recovery without manual intervention.
  • Configurable thresholds let you tune sensitivity to failures.
  • Improves overall reliability and user experience.

Not-so-good things

  • Adds extra code and architectural complexity.
  • Requires careful tuning of thresholds and timeout values.
  • May mask underlying problems if over-relied upon.
  • Introduces a short delay before requests can resume, which can affect latency.