> For the complete documentation index, see [llms.txt](https://docs.umbraco.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.umbraco.com/umbraco-cms/extend-your-project/backoffice-extensions/extending-overview/extension-types/collections.md).

# Collections

A Collection is an extension that fetches and exposes a list of entities in the Umbraco backoffice. It connects a **Collection Repository**, for fetching data, and one or more **Collection Views** (the display layer).

The Collection itself does not render anything. It manages pagination, filtering, and selection state — the Collection Views decide how items are presented.

## How the parts relate

| Part                      | Role                                                      |
| ------------------------- | --------------------------------------------------------- |
| **Collection**            | Registers the extension and points to a repository alias. |
| **Collection Repository** | Fetches and returns items.                                |
| **Collection View**       | Bound to the collection via its alias; renders the items. |

## Articles

* [Collection](/umbraco-cms/extend-your-project/backoffice-extensions/extending-overview/extension-types/collections/collection.md)
* [Collection View](/umbraco-cms/extend-your-project/backoffice-extensions/extending-overview/extension-types/collections/collection-view.md)


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