An Eventuate ES application consists of the following types of modules:

• Command-side module: It creates, updates, and aggregates objects that implement business logic and are persisted using event sourcing, in response to external update requests (usually HTTP POST, HTTP PUT, and HTTP DELETE requests) using services objects, and events published by command-side aggregates.
• Query-side module: It maintains the materialized CQRS views of command-side aggregates. This module has two sub-modules, as follows:
  • View update module: This subscribes to events to update the view
  • View query module: This handles query requests by querying the view
• Outbound gateway module: This processes events by invoking external services.

Eventuate ES has some limitations in relation to saga management, mainly involving the complexity of the platform and the restrictions placed by the CQRS pattern.