There is no "key" for stuff that was purchased on Steam.

Also, in general, Steam does not tell you the key that you used. There's no useful application for this anyway, since the key is now useless.

Originally posted by Arex:

Check key code for purchased game

Hello, guys. Can somebody help me, how to check key code, that was used for activated game in my library?
But not from other sources, like humble bundle, ea, ubisoft, etc., but from steam within.
Thanks in advance

Steam doesn't sell keys.

When a game needs an activation.code it should be automatically added or displayed by steam, usually its just needed if you run them without steam though, after failed updates. I had that problem on dominions once - steamworks seem to be blamed.
I cant tell if theres a way to get the code from steam "manually" - maybe just reinstall the game.

Originally posted by waTTe:

When a game needs an activation.code it should be automatically added or displayed by steam,

In those rare cases, the game will have a "CD keys" entry in the "Manage" menu on the library.

ok, thanks everyone for your answers