Roblox is a family friendly sandbox MMO designed to appeal mainly to kids 4-14. Players can create their building-block avatar, explore the virtual world and interact socially, construct many different types of buildings as well as create games of their own with the built-in accessible tools. Once approved, these user-generated games are available for multiplayer participation via the game's client or website. When other players visit their creations, users earn in-game currency, which can be exchanged for clothes and building materials.

Roblox has moderators always on to help make everything safe for kids, offers a parent account feature, and allows for privacy controls on who can visit user created games and properties. While Roblox is free to play, there is an item shop for paid upgrades, or an optional subscription available that offers many additional bonuses.