Validate invite token API
From Warzone Wiki
If you're creating a system that invites players to WarLight games via the Create game API, you may wish to validate whether or not an invite token or e-mail address is valid before you attempt to invite them to a game.
Of course, if you invite a player to a game with their token, the Create game API will inform you that it's invalid. But you may wish to determine whether or not it's valid before attempting to create a game, such as when a new player signs up on your site.
You can do this by calling the following API: http://warlight.net/API/ValidateInviteToken.aspx?Token=12345678
In place of the "Token" parameter, you may place an invite token number or an e-mail address that a user has provided you.