Poll whether an authentication request was confirmed

Using the token acquired in the start endpoint, you can start polling this endpoint once every 10 seconds.

When the user has confirmed the authentication request on their end, this endpoint will return the user's API key that you can use in subsequent authenticated endpoints. Note that it'll do so only once, subsequent requests after the initial 200 response will return a 404.

For as long as the user did not yet confirm their authentication request, this endpoint will return a 403.