title: How To Programmatically Check Tumblr Username Availability?
body: <p>is there any way to check for username availability for tumblr? i want to check if a username is available to register on tumblr. </p>
  
  <p>I tried checking HTTP response of urls like username.tumblr.com but the one that returns 404 are still not available for registration. Any idea?
  Thanks!</p>