The Retry pattern improves fault tolerance in microservices by automatically re-attempting a failed operation, letting the system recover from transient issues without requiring manual intervention or failing the entire request outright.
Key Points: • Many failures in distributed systems are transient — brief network timeouts, momentary resource contention — and simply succeed on a second or third attempt. • Automatic retries mean a temporary blip doesn't need to surface as a user-visible error, improving perceived reliability. • Combined with exponential backoff, retries give a struggling downstream service breathing room to recover instead of hitting it again immediately. • Retry should be scoped to idempotent operations, or ones made safe to repeat, since retrying a non-idempotent operation (like charging a card twice) can cause real damage. • On its own, Retry doesn't handle sustained outages well, which is why it's typically combined with a Circuit Breaker to stop retrying once a service is clearly down.
Example: A brief 200ms network timeout calling the Inventory Service might resolve itself on the very next retry attempt, so the end user never even notices anything went wrong, whereas without retries that same blip would surface as a failed request.
Interview Tip: A concise interview answer is:
"The Retry pattern improves fault tolerance by automatically re-attempting operations that fail due to transient issues, which recovers from brief network timeouts or momentary unavailability without the user ever seeing an error. It has to be scoped to idempotent operations and paired with backoff and a circuit breaker so it helps with recoverable blips without making a real outage worse."