Hello, I want to know is possible somehow to if you have any type application which works with steam keys, after user buys or activates gift or activates key from third party resellers to send key to publisher server so internal authentifaction system could recognize key or should I instead save user steam id and then identificate if he has my app. Probably it looks like noobie question, but this is my first time with steam so thank you very much for explanation.
Since steam does not fully reveal how keys are managed by steam to publisher, so I would like to know if they have such event after key is activated in steam