# Global Events Add-on
## Overview
The standard CUBA [Events](https://doc.cuba-platform.com/manual-latest/events.html) interface allows you to publish events that can be received by subscribers within the same application block. So there are no built-in facilities for notifying clients from middleware or propagating events in the cluster.
The Global Events add-on enables receiving Spring's application events on any application block of the distributed system. In the simplest configuration with `core` and `web` blocks running in a single JVM, it allows you to send events from `core` to `web` to notify UI screens or managed beans. In a cluster environment, an event published inside a block, will be received on all other connected parts of the system: on all middleware blocks and on the clients: `web` and `portal`.
In case of the client is deployed in the same JVM as middleware and `cuba.useLocalServiceInvocation` application property is set to `true`, it registers a callback in the `LocalRegistry` class located in the `shared-lib` module which is accessible to both middleware and the client.
In a distributed environment, clients open WebSocket connections to the middleware blocks, and middleware exchange events in a usual way using the cluster communication mechanism.
## Installation
The add-on can be added to your project in one of the ways described below. Installation from the Marketplace is the simplest way. The last version of the add-on compatible with the used version of the platform will be installed.
Also, you can install the add-on by coordinates choosing the required version of the add-on from the table.
In case you want to install the add-on by manual editing or by building from sources see the complete add-ons installation guide in [CUBA Platform documentation](https://doc.cuba-platform.com/manual-latest/manual.html#app_components_usage).
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