A circuit breaker prevents cascade failures by detecting when an external service is failing and temporarily stopping requests. When failures exceed a threshold, it trips open and fails fast instead of waiting for timeouts. For businesses, this means one broken integration cannot take down your entire platform.
Your payment integration times out. Your system retries. And retries. And retries.
200 requests pile up behind the failed one. Your database buckles. Your entire platform goes down.
One broken integration just took down everything. For hours.
The fastest way to recover from failure is to stop trying.
QUALITY & RELIABILITY LAYER - Stop one failure from becoming many.
A safety switch for your integrations
A circuit breaker monitors the health of external services and integrations. When failures cross a threshold, it trips open and stops sending new requests. Instead of hammering a broken service (making things worse), the system fails fast and gracefully.
The pattern comes from electrical engineering. A circuit breaker protects your house when too much current flows. Trip the breaker, and the house stays safe while you fix the problem. Same principle applies to software: trip the breaker, and your system stays healthy while the external service recovers.
Without circuit breakers, a 5-second timeout on one API can become a 5-minute outage for your entire platform. With them, one failure stays contained as one failure.
Circuit breakers solve a universal problem: how do you stop one point of failure from cascading through an entire system? The same pattern appears anywhere dependent components can drag each other down.
Monitor requests for failures. When failures exceed a threshold, stop sending new requests. Wait for recovery. Test with occasional requests. When successful, resume normal operation.
Toggle the external service to "Down" and send requests. Watch your system crash. Then enable circuit breaker and try again.
Click to cycle: healthy / degraded / down
Three states that protect your system
Requests flow normally
The circuit is closed. All requests pass through to the external service. The breaker monitors success and failure rates, tracking recent history to detect problems.
Requests fail immediately
The circuit is open. New requests fail immediately without contacting the external service. This prevents piling more load on a broken service and protects your system from resource exhaustion.
Probing for recovery
After a timeout period, the breaker allows limited requests through to test if the service has recovered. Success closes the circuit; failure opens it again for another timeout period.
Answer a few questions to get a recommended configuration for your situation.
How many requests per minute to this service?
The payment provider had a 5-minute outage. But without circuit breakers, every checkout request waited 30 seconds to timeout. Connection pools exhausted. The queue backed up. Other features that share resources went down. A 5-minute external issue became a 2-hour platform outage.
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This component works the same way across every business. Explore how it applies to different situations.
Notice how the core pattern remains consistent while the specific details change
You configure the breaker to trip after 50 failures in a minute. But with 100 requests per second, by the time it trips, 3,000 failed requests have already piled up and your database connection pool is exhausted.
Instead: Set thresholds based on acceptable impact, not arbitrary numbers. 5-10 failures in 30 seconds is often enough to detect a problem.
The circuit breaker trips and starts returning errors immediately. But your application does not know what to do with those errors. Users see blank screens or cryptic error messages.
Instead: Design fallback behavior before implementing circuit breakers. Cached data, degraded functionality, or clear user messaging.
You use one circuit breaker for all external APIs. When the payment service fails, it trips the breaker and blocks your email sending, analytics, and everything else.
Instead: One circuit breaker per external dependency. Each service fails independently.
A circuit breaker is a design pattern that prevents cascade failures by monitoring external service health. When failures exceed a threshold, the circuit trips open and fails requests immediately instead of waiting for timeouts. This protects your system from resource exhaustion when dependencies fail. The pattern mirrors electrical circuit breakers that trip to prevent house fires.
Use circuit breakers whenever your system depends on external services that can fail: payment processors, email providers, third-party APIs, AI services. If a single service timing out could exhaust your connection pool or thread pool, you need a circuit breaker. They are especially critical for high-volume services where failures compound quickly.
Circuit breakers have three states: Closed (normal operation, requests pass through), Open (tripped, requests fail immediately), and Half-Open (testing recovery with limited requests). Failures transition from Closed to Open. A timeout transitions from Open to Half-Open. Success in Half-Open returns to Closed; failure returns to Open.
Start with 5 failures in 30 seconds for most services. High-volume services (hundreds of requests per second) can use tighter windows like 5 failures in 10 seconds. Critical services may trip after just 2-3 failures. The key is detecting problems before cascade effects, not waiting until damage is done. Tune based on observed failure patterns.
Retry logic attempts the same request multiple times hoping for success. Circuit breakers stop all requests when failure is detected. They work together: retries handle transient failures, circuit breakers prevent retries from hammering a truly failed service. Without circuit breakers, retry logic makes cascade failures worse by multiplying load on failing services.
When a circuit breaker trips, your application knows the service is unavailable and can activate fallback behavior: serve cached data, switch to backup services, or present reduced functionality. Without circuit breakers, your code just sees timeouts and errors. The circuit breaker gives you a clear signal to trigger degradation logic.
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Choose the path that matches your current situation
You have no failure isolation between services
You have circuit breakers but no fallback behavior
Circuit breakers work but configuration is guesswork
You have learned how to stop failures from cascading through your system. The natural next step is understanding how to maintain partial functionality when components fail.