# Validation Settings API

This API is available to Validation Settings extensions. Refer to the [tutorial](https://shopify.dev/docs/apps/checkout/validation/create-complex-validation-rules) for more information. Note that the [`FunctionSettings`](https://shopify.dev/docs/api/admin-extensions/components/forms/functionsettings) component is required to build Validation Settings extensions.

## applyMetafieldChange

Applies a change to the validation settings.

### ApplyMetafieldChange

#### Returns: Promise<MetafieldChangeResult>

#### Params:

- change: MetafieldChange
export type ApplyMetafieldChange = (
  change: MetafieldChange,
) => Promise<MetafieldChangeResult>;


### MetafieldUpdateChange

### key

value: `string`


### namespace

value: `string`


### type

value: `"updateMetafield"`


### value

value: `string | number`


### valueType

value: `SupportedDefinitionType`


### MetafieldRemoveChange

### key

value: `string`


### namespace

value: `string`


### type

value: `"removeMetafield"`


### MetafieldChangeSuccess

### type

value: `"success"`


### MetafieldChangeResultError

### message

value: `string`


### type

value: `"error"`


## data

The object that exposes the validation with its settings.

### ValidationData

The object that exposes the validation with its settings.

### shopifyFunction

value: `ShopifyFunction`


### validation

value: `Validation`


### ShopifyFunction

### id

value: `string`

the validation function's unique identifier

### Validation

### id

value: `string`

the validation's gid when active in a shop

### metafields

value: `Metafield[]`

the metafields owned by the validation

### Metafield

### description

value: `string`


### id

value: `string`


### key

value: `string`


### namespace

value: `string`


### type

value: `string`


### value

value: `string`