# Repositories

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This page is a work in progress and may undergo further revisions, updates, or amendments. The information contained herein is subject to change without notice.
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A repository serves as the Backoffices entry point for requesting data and getting notified about updates. Each domain should register its own repository in the Backoffice.

### Register a Repository <a href="#register-a-repository" id="register-a-repository"></a>

```typescript
import { umbExtensionsRegistry } from '@umbraco-cms/backoffice/extension-registry';
import { MyRepository } from './MyRepository';

const repositoryManifest = {
 type: 'repository',
 alias: 'My.Repository',
 name: 'My Repository',
 api: MyRepository,
};
```

Repositories can use different data sources depending on the state of the application. The data sources can come from places like a server, an offline database, a store, or a Signal-R connection. That means that the consumer will not have to be concerned how to access the data, add or remove items from a collection, etc. This means we get a loose connection between the consumer and the data-storing procedures, hiding all complex implementation.

### Data flow with a repository <a href="#data-flow-with-a-repository" id="data-flow-with-a-repository"></a>

<figure><img src="/files/lJgji0SVZFkITXUqYLGH" alt=""><figcaption><p>Data flow</p></figcaption></figure>

A repository must be instantiated in the context where it is used. It should take a host element as part of the constructor. This ensures that any contexts consumed in the repository, like notifications or modals, are rendered in the correct DOM context.

A repository can be called directly from an element, but will often be instantiated in a context, like the Workspace Context.


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# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.umbraco.com/umbraco-cms/16.latest/customizing/foundation/repositories.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.