To work effectively with cloud resources, we need to choose the right set of patterns and services for our organization. Today, most cloud-native platforms and applications support eventing. In this section, we will cover the characteristics of events with some basic definitions:

• Scatter communications: The event source broadcasts the events to a wider audience. One or more interested event consumer applications or software instances can react and consume those emitted events.
• Event timeliness: The event source publishes events in real time, instead of storing them locally, for event consumers to consume the event.
• Asynchronous communication: Communication between the event source and the event handler is asynchronous. The event source does not wait for the consuming application to respond to events.
• Single event: The event source publishes an individual event, as opposed to a single aggregated event. This makes the event lightweight when traversing the communication channel, and means the event handler can run each event as a separate task.
• Expression of interest: This refers to receiving systems being able to express interest in the events of their choosing rather than having to react to all the events generated.
• Dependency reversal: This is another key characteristic of an event-driven architecture. As an enterprise moves to a distributed architecture, the enterprise does not want the application to be monolithic. An intermediate layer between applications and systems minimizes the dependency, and each application can be enhanced without breaking the communication pattern.

If all this is taken into account, an enterprise can make an informed decision about the messaging micro component to use, based on its business requirements. For the rest of the chapter, we will concentrate on the capabilities of Azure Event Grid, defining Azure Event Grid's building blocks and then moving on to Azure Event Grid's capabilities for building real-time, interactive solutions.