Q48: How do you scale GraphQL Subscriptions across distributed clusters?
Single-server WebSocket instances cannot scale horizontally alone. Distributed subscriptions require a pub/sub backbone (e.g., Redis Pub/Sub, NATS, Kafka). When an event occurs on any node, it publishes to the broker, which broadcasts the event to all connected WebSocket servers holding active subscriptions.
Key Takeaways
- Scaling subscriptions horizontally requires central pub/sub message brokers (Redis/Kafka).
Knowledge Check
Which component coordinates real-time event distribution across multiple stateless GraphQL server nodes?