System design interview strategies covering fault tolerance, circuit breakers, idempotency, rate limiting, and graceful degradation.
Practice This QuestionDesign with the mindset that network partitions, hardware failures, and dependency outages will happen.
Use exponential backoff with jitter and circuit breakers (Resilience4j/Envoy) to prevent cascading failures.
Ensure APIs handle duplicate requests gracefully using idempotency keys.
Fall back to cached data or degraded features when downstream dependencies fail.
“Designing resilient distributed systems starts with assuming everything will fail. First, I isolate services using failure-containment patterns like circuit breakers and bulkheads so a failure in a minor service doesn't cascade to core APIs. Second, for asynchronous inter-service communication, I design idempotent message consumers with dead-letter queues (DLQs) and exponential backoff retries with random jitter. Third, I ensure graceful degradation—for example, if our recommendation engine goes down, the client app falls back to a cached static trending list. Finally, we conduct chaos testing (using tools like Gremlin) in staging to validate system resilience under real network latency.”
“I implement rate limiting at the API gateway, set strict HTTP request timeouts, and use Redis caches for fallback data so the user experience remains smooth during backend issues.”
“I make sure service calls include timeout configurations and retry logic so temporary network hiccups don't cause user errors.”
| Word | ❌ Common Error | ✅ Correct | Tip |
|---|---|---|---|
| idempotency | eye-dem-po-ten-see | eye-dem-POH-tuhn-see | Stress on 'POH'. |
| resilient | re-si-lent | ri-ZIL-yuhnt | Stress second syllable 'ZIL'. |
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