There is no possible way to check whether a key is valid without activating it. Steam will never create a system to check keys because, simply put, they don't want people trading keys. Games purchased from their store have the trading privileges.
Sorry, you're not the only one who wants it :(
Comment has been collapsed.
If it says you already have the game, then the game you're trying is already in your library. Chances are the keys are unused. I doubt you get that message if the key is invalid.
Comment has been collapsed.
You can check if a key is used or not by contacting steam support. All they can tell you is weather the key is used or not. They can't tell you who used the key.
Comment has been collapsed.
9 Comments - Last post 34 minutes ago by pb1
160 Comments - Last post 45 minutes ago by bob12857
45 Comments - Last post 48 minutes ago by gonsi
125 Comments - Last post 1 hour ago by ewoda
1,214 Comments - Last post 2 hours ago by CasualGamerMe
111 Comments - Last post 5 hours ago by Bohemius
16,702 Comments - Last post 5 hours ago by mjy
36 Comments - Last post 1 minute ago by AceBerg42
31 Comments - Last post 3 minutes ago by Keka
359 Comments - Last post 10 minutes ago by Patzl
29,604 Comments - Last post 10 minutes ago by Masafor
909 Comments - Last post 14 minutes ago by shortyginger
180 Comments - Last post 21 minutes ago by AceBerg42
134 Comments - Last post 26 minutes ago by shortyginger
I have keys for 3 games that I currently have in my library, and I want to make giveaways from them
the proble is: I don't know if the keys are used or not.
I have the games, and when I put the keys to activate them, appears the message: you already have the game, so you can't activate this key.
I tried to activate USED keys just for test and I receive the message: invalid key
I asked some people and they say that invalid key is not the message of an used key.
now my mind is playing tricks on me, so anyone knows how to know if a key is used? xD
Comment has been collapsed.