thank you so much, this helps, the only thing I see with this solution is we have to do at least two request to the api one: to get the user id of the username you want to check and two: to check the relationship between that userid and yours, so, if you want to check a bunch of username maybe your application will be a little be slow
but that is something that I have to handle, right?
If you really can’t spare the extra request, you could always use Kraken v3 until it gets removed at the end of the year. Although the existing documentation has since been removed from the github repository.
I would do what @3ventic suggested, and then cache the id/login pair for future requests.