What types of data are suitable for event-driven architectures, and what types of events can you describe?

In an event‑driven architecture, the data should be granular, time‑stamped, and immutable so that each event can be processed independently. Typical event data includes user actions (clicks, purchases), system logs, IoT sensor readings, and transactional updates. Events are usually represented as JSON or Avro messages with a clear schema. The types of events you can describe are: 1) Command events – actions that change state (e.g., "OrderPlaced"). 2) Query events – requests for information (e.g., "GetUserProfile"). 3) Domain events – state changes that other services react to (e.g., "PaymentProcessed"). 4) System events – infrastructure signals (e.g., "InstanceStarted"). Choosing the right event type depends on the business requirement and the downstream consumers.