This build to me is what makes viper seem an escape artist and oportunitist. This build IS FOR 1 V 1s! If you scale hard enough, you will BE the problem for the other team.
The point of this build is to stay in lane as long as you can to farm the most you possibly throught the game.
Most of the items listed are organized from left to right for consistent matches.
Early game viper is really good, poke the enemy hero as much as you can. you have a lot of dmg from your weapon. Lastly and the most important imo is to SLIDE EBERYWHERE.