curl --request POST \
  --url https://{subdomain}.auth.{region}.nhost.run/v1/signin/anonymous \
  --header 'Content-Type: application/json' \
  --data '{
  "displayName": "John Smith",
  "locale": "en",
  "metadata": {
    "firstName": "John",
    "lastName": "Smith"
  }
}'

{
  "session": {
    "accessToken": "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9...",
    "accessTokenExpiresIn": 900,
    "refreshTokenId": "2c35b6f3-c4b9-48e3-978a-d4d0f1d42e24",
    "refreshToken": "2c35b6f3-c4b9-48e3-978a-d4d0f1d42e24",
    "user": {
      "avatarUrl": "https://myapp.com/avatars/user123.jpg",
      "createdAt": "2023-01-15T12:34:56Z",
      "defaultRole": "user",
      "displayName": "John Smith",
      "email": "john.smith@nhost.io",
      "emailVerified": true,
      "id": "2c35b6f3-c4b9-48e3-978a-d4d0f1d42e24",
      "isAnonymous": false,
      "locale": "en",
      "metadata": {
        "firstName": "John",
        "lastName": "Smith"
      },
      "phoneNumber": "+12025550123",
      "phoneNumberVerified": false,
      "roles": [
        "user",
        "customer"
      ],
      "activeMfaType": "<string>"
    }
  }
}