> ## Documentation Index
> Fetch the complete documentation index at: https://auth0-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 {
  type: IdentifierType;
  required: boolean;
}
```

## Properties

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

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