Can you play online thru a family sharing library

[mute]

so my friend gave me his library thru family share i was wondering if u could play multiplayer thru the game i launched thru his library

[Wolf Knight]

you cannot play against your friend, only one account can be online using the library. if you want to play against your friend, both of you will need to have the game in your library

[Ogami]

Also you cant play games that use third party servers to login. For example GTA 5, all Ubisoft games and so on.

[Cathulhu]

Sure, but not with your friend. Only one user can access a Steam library at any given time.