What is Azure Event Grid and how does it differ from Event Hubs and Service Bus?

Azure Event Grid is a fully managed event routing service for reactive, event-driven architectures. It routes events from sources (Azure services, custom apps) to handlers (Functions, Logic Apps, webhooks) using a push model. It is designed for discrete events (resource created, file uploaded) at 10 million events/second with sub-second latency. Comparison: Event Grid: low-latency, reactive event distribution; events are small notifications; no ordering guarantee; best for triggering actions. Event Hubs: high-throughput telemetry streaming; data retained for replay; partitioned for parallel consumption; best for log/telemetry ingestion. Service Bus: enterprise messaging with guaranteed delivery, ordering, transactions, and dead-letter queues; best for business workflows requiring reliability. Use them together: Event Hubs ingests, Event Grid reacts, Service Bus coordinates business processes.