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+---
+sidebar_position: 17
+---
+
+# Extensions
+
+Extensions are a way to add project-specific or domain-specific functionality without adding that functionality directly to the OpenRemote core.
+
+An extension is packaged as a separate Java artifact and can provide additional capabilities such as protocol agents, asset types, setup tasks, container services, rules, or other reusable backend logic.
+
+Extensions help keep the OpenRemote core smaller and easier to maintain.
+They also make it easier to reuse functionality across multiple custom projects.
+
+## Using extensions
+
+Currently, extensions are used by adding them as dependencies to a custom project.
+
+For example, the ENTSO-E extension can be added to the [dependencies block](https://github.com/openremote/custom-project/blob/d48cd93a21873e62df7fe5f79dce0624f3cfc972/manager/build.gradle#L3-L8) of the manager project in your custom project:
+
+```groovy
+dependencies {
+    api "io.openremote.extension:openremote-entsoe-extension:0.5.1"
+}
+```
+
+After the custom project is rebuilt and the OpenRemote Manager is restarted, the extension is available as part of that deployment.
+
+For more details about the extension architecture and implementation approach, see the [extensions design document](https://github.com/openremote/extensions/pull/9).
+
+## Current extensions
+
+The current extensions are available in the [extensions repository](https://github.com/openremote/extensions/):
+
+* [EMS](https://github.com/openremote/extensions/tree/main/ems): A new extension-based implementation of the Energy Management System with GOPACS support.
+* [ENTSO-E](https://github.com/openremote/extensions/tree/main/entsoe/): Agent for retrieving ENTSO-E energy price data and storing it as predicted datapoints.
+
+## Current status
+
+The extension mechanism is currently build-time based.
+This means extensions cannot yet be installed, enabled, or disabled dynamically from the Manager UI.
+
+We are also working on moving more reusable and domain-specific code out of the main OpenRemote repository and into the [extensions repository](https://github.com/openremote/extensions/).
+Over time, this should make the main repository leaner while making optional functionality easier to package, maintain, and reuse.
+
+You can follow the ongoing work in the [extensions epic](https://github.com/openremote/openremote/issues/2598).