> ## Documentation Index
> Fetch the complete documentation index at: https://docs-dev-docs-event-stream-action-templates.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Identifier

Describes a configured identifier field (e.g. email, phone, or username)
for use in a signup form or authentication flow.

```ts Example theme={null}
export interface Identifier {
  /**
   * The type of identifier, such as `'email'`, `'phone'`, or `'username'`.
   *
   * @see IdentifierType
   */
  type: IdentifierType;

  /**
   * Whether this identifier is required for signup.
   */
  required: boolean;
}
```

## Example

```ts theme={null}
const emailIdentifier: Identifier = {
  type: 'email',
  required: true
};
```

## Properties

<ParamField body="required" type="boolean">
  Whether this identifier is required for signup.
</ParamField>

<ParamField body="type" type={<span><a href="/docs/libraries/acul/js-sdk/Screens/type-aliases/ScreenIdentifierType">ScreenIdentifierType</a></span>}>
  The type of identifier, such as `'email'`, `'phone'`, or `'username'`.

  Type
</ParamField>