> 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/value-type.md).

# Value Type

In an extensible system, different parts of the codebase need to agree on what kind of data they are working with. A value type is the contract that makes this possible — a named string constant that identifies the kind of data a value holds. Define one, and you get compile-time autocomplete and type checking wherever value-type keys are accepted across the system. [Value Summary](/umbraco-cms/extend-your-project/backoffice-extensions/extending-overview/extension-types/value-summary.md) extensions are one example of where value types are used to match a value to the right renderer.

## Built-in types

For common values, the core package already provides value types you can use directly. Import them from `@umbraco-cms/backoffice/value-type`.

| Constant                   | Key                      | TypeScript type     |
| -------------------------- | ------------------------ | ------------------- |
| `UMB_STRING_VALUE_TYPE`    | `Umb.ValueType.String`   | `string`            |
| `UMB_BOOLEAN_VALUE_TYPE`   | `Umb.ValueType.Boolean`  | `boolean`           |
| `UMB_DATE_TIME_VALUE_TYPE` | `Umb.ValueType.DateTime` | `string` (ISO 8601) |

If your data matches one of these, you can use the constant directly without defining your own.

## Defining a value type

When none of the built-in types describe your data, define your own. Declare a constant with `as const` and extend the global `UmbValueTypeMap` interface in the same file. The TypeScript type you assign is the shape of the data this value type represents:

{% code title="my-feature/value-type/constants.ts" %}

```typescript
export type MyStatusValue = 'active' | 'inactive' | 'pending';

export const MY_STATUS_VALUE_TYPE = 'My.ValueType.Status' as const;

declare global {
  interface UmbValueTypeMap {
    [MY_STATUS_VALUE_TYPE]: MyStatusValue;
  }
}
```

{% endcode %}

Export the constant from your package entry point so other packages can import and use it.

### Naming

Follow the pattern that matches your use case:

| Category                  | Pattern                         | Example                            |
| ------------------------- | ------------------------------- | ---------------------------------- |
| Primitive or basic value  | `My.ValueType.{Type}`           | `My.ValueType.Status`              |
| Domain — reference shapes | `My.ValueType.{Entity}.{Shape}` | `My.ValueType.Category.References` |
| Property editor           | Property editor schema alias    | `My.PropertyEditor.Alias`          |

For property editors, always use the schema alias as the key. See [Property Editor Value Summary](/umbraco-cms/extend-your-project/backoffice-extensions/property-editors/property-editor-value-summary.md) for details on why.

## Use cases

Value types are used in these extension points:

{% content-ref url="/pages/CfTq2NNQNjVCwJPOiWXT" %}
[Value Summary](/umbraco-cms/extend-your-project/backoffice-extensions/extending-overview/extension-types/value-summary.md)
{% endcontent-ref %}

{% content-ref url="/pages/46n5THfxnrq8PNB4OHlW" %}
[Property Editor Value Summary](/umbraco-cms/extend-your-project/backoffice-extensions/property-editors/property-editor-value-summary.md)
{% endcontent-ref %}


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