<p>Registers (or retrieves) a Cognito <code>IdentityId</code> and an OpenID Connect token for a user authenticated by your backend authentication process. Supplying multiple logins will create an implicit linked account. You can only specify one developer provider as part of the <code>Logins</code> map, which is linked to the identity pool. The developer provider is the "domain" by which Cognito will refer to your users.</p> <p>You can use <code>GetOpenIdTokenForDeveloperIdentity</code> to create a new identity and to link new logins (that is, user credentials issued by a public provider or developer provider) to an existing identity. When you want to create a new identity, the <code>IdentityId</code> should be null. When you want to associate a new login with an existing authenticated/unauthenticated identity, you can do so by providing the existing <code>IdentityId</code>. This API will create the identity in the specified <code>IdentityPoolId</code>.</p> <p>You must use AWS Developer credentials to call this API.</p>

{
  "success": true,
  "data": {
    "id": "abc123",
    "created_at": "2025-01-01T00:00:00Z"
  }
}

{
  "success": false,
  "error": {
    "code": "VALIDATION_ERROR",
    "message": "Invalid request parameters"
  }
}