We have an item in our store that is for a third party service, the user simply gets a code they use at the third party.

How can I send this code out automatically to the user when their payment is confirmed?

 

I looked at licensing keys, but they seem to only support auto-generated keys, we have a static key. (And you can't use the key on our site)

One idea is that IP.Commerce supports a redirect to a custom page at the end of purchase.  So once a user completes the purchase, they would redirect to a custom page you create that can show them the key if the key will always be the same.