name -> uuid through api.mojang.com

gistfile1.php

<?php

// insert paid usernames here (duh)
$name = ["jeb_", "notch"];
$game = "minecraft";
$api = "https://api.mojang.com/profiles/";

// request options
$opts = stream_context_create(['http'=>['method'=>'POST','header'=>'Content-type: application/json','content'=>json_encode($name)]]);
$request = json_decode(file_get_contents($api.$game, false, $opts), true);
if (empty($request)) {
  printf("user not found: %s", $name);
  exit;
}

foreach($request as $profile){
  printf("username: %s -- uuid: %s\n", $profile["name"], $profile["id"]);
}