If you purchase Factorio directly from the official website , you are eligible for a free Steam key to add the game to your Steam library. This allows players to own both the standalone, DRM-free version and the Steam-integrated version without paying twice.
If you decide to buy, get it directly from (gives a Steam key + DRM-free copy) or Steam .
If you see a site offering one, treat it as a scam . The safest path is: