Plugins are packaged [Django](https://docs.djangoproject.com/) apps that can be installed alongside NetBox to provide custom functionality not present in the core application. Plugins can introduce their own models and views, but cannot interfere with existing components. A NetBox user may opt to install plugins provided by the community or build his or her own.
* **Add content to existing model templates.** A template content class can be used to inject custom HTML content within the view of a core NetBox model. This content can appear in the left side, right side, or bottom of the page.
* **Add navigation menu items.** Each plugin can register new links in the navigation menu. Each link may have a set of buttons for specific actions, similar to the built-in navigation items.
* **Add custom middleware.** Custom Django middleware can be registered by each plugin.
* **Declare configuration parameters.** Each plugin can define required, optional, and default configuration parameters within its unique namespace. Plug configuration parameter are defined by the user under `PLUGINS_CONFIG` in `configuration.py`.
* **Modify core models.** Plugins may not alter, remove, or override core NetBox models in any way. This rule is in place to ensure the integrity of the core data model.