title: How does one prevent duplicate listings on ebay when running AddItem simultaneously?
body: <p>I have a little big problem when it comes to adding listings on eBay via the API.<br>
  Currently I'm running my &quot;Add&quot;-script (that uses AddFixedPriceItem and picks 20 Items) 4 times each 2nd Minute.<br>
  To prevent duplicates I set an according script-id to each entry in the Database but sometimes there are still duplicates on eBay even though they're all unique entries.</p>
  <p>Now I was thinking about UUIDs created from the title like:</p>
  <pre><code>$uuid = md5($title);
  </code></pre>
  <p>but is this even a good practice?<br>
  I read that UUIDs should be randomly created and only used one time. Is this true?<br>
  Maybe you also ran into such a problem and found a solution.</p>