Even thou all these services deal with the transfer of data from source to target and might seem similar falling under the umbrella messaging services they do differ in their intent.
High-level definition:
Azure Event Grids – Event-driven publish-subscribe model (think reactive programming)
Azure Event Hubs – Multiple source big data streaming pipeline (think telemetry data)
Azure Service Bus- Traditional enterprise broker messaging system (Similar to Azure Queue but provide many advanced features depending on use case full comparison)
Difference between Event Grids & Event Hubs
Event Grids doesn’t guarantee the order of the events, but Event Hubs use partitions which are ordered sequences, so it can maintain the order of the events in the same partition.
Event Hubs are accepting only endpoints for the ingestion of data and they don’t provide a mechanism for sending data back to publishers. On the other hand, Event Grids sends HTTP requests to notify events that happen in publishers.
Event Grid can trigger an Azure Function. In the case of Event Hubs, the Azure Function needs to pull and process an event.
Event Grids is a distribution system, not a queueing mechanism. If an event is pushed in, it gets pushed out immediately and if it doesn’t get handled, it’s gone forever. Unless we send the undelivered events to a storage account.
