Circuit Breaker Pattern

Prevents cascading failures when your dependencies go down by wrapping calls in a state machine that trips open after repeated failures, then periodically tests if the service has recovered. Includes TypeScript, Python, and Java implementations with configurable failure thresholds, timeout handling, and half-open testing states. The monitoring examples are solid if you're running this in production. Honestly essential for any system calling flaky external APIs or microservices, though you'll want to tune the thresholds carefully since the defaults won't match your actual traffic patterns. The Opossum and Resilience4j style guides are nice if you're familiar with those libraries.