Practice the English vocabulary for event-driven systems: events, streams, consumers, choreography, and eventual consistency.
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How would you explain 'event-driven architecture' to a non-technical stakeholder?
In event-driven architecture, components emit events when something happens; other components react to those events independently. This decouples producers from consumers.
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What is the difference between 'choreography' and 'orchestration' in event-driven systems?
In choreography, each service knows what to do when it receives an event — there is no central coordinator. In orchestration, a central service (orchestrator) explicitly commands each step.
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What does 'event sourcing' mean?
Event sourcing stores every change as an immutable event. Current state is derived by replaying the event log. This provides full audit history and the ability to reconstruct past states.
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Which sentence best describes 'eventual consistency' in an event-driven system?
Eventual consistency means that all nodes will converge to the same state once all events have propagated — but temporarily, different parts of the system may see different states.
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What is a 'dead letter queue' (DLQ)?
A dead letter queue captures messages that failed processing (after retries are exhausted). It allows teams to inspect, debug, and replay failed messages without losing them.
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How would you describe 'consumer group' in the context of Apache Kafka?
A consumer group allows multiple consumer instances to share the processing of a topic's partitions. Each partition is assigned to exactly one consumer in the group, enabling parallel processing.
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What does 'idempotent consumer' mean?
An idempotent consumer handles duplicate message delivery gracefully. Since message brokers may deliver the same message more than once (at-least-once delivery), consumers must be designed so duplicates have no harmful effect.
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What is a 'saga' pattern in event-driven microservices?
The saga pattern manages distributed transactions across microservices. Each service does its local transaction and emits an event. On failure, compensating transactions (rollback events) undo previous steps.