The green dot on Snapchat is an Activity Indicator that appears next to a person's profile icon or Bitmoji mainly in the "Add Friends" or "Quick Add" screen. It means that the person has been active on Snapchat recently, typically within the last 24 hours, but does not necessarily mean they are currently online at that exact moment. This feature helps users know who has been actively using Snapchat recently and enables immediate conversations if desired. This indicator, visible even if you are not friends with the user, can be turned off by disabling the Activity Indicator in Snapchat settings to maintain privacy. It does not appear in chat windows, only in friend-adding- related screens. The green dot usually vanishes after 24 hours of inactivity or if the user chooses to hide it.