Developers are people who have uploaded a game to Kongregate. Strictly speaking, uploads do not have to be games, but Kongregate do require any uploads to have some form of inter-activity. Stats submissions are considered inter-activity, which allows Idle Games to be uploaded to the site.
Developers have the symbol after their name in the chat, which denotes that the user has created a game. There are several different programs and tools that can be used for creating Flash or Unity3D games. Developers can also implement the Kongregate API in the game, enabling high scores and stat submissions. If a game gets a high rating and contains the API, Kongregate may create badges for the game.
Kongregate requires any uploaded games to have some form of inter-activity. As stats submissions are considered inter-activity, idle games are allowed to be uploaded to the site. Tools and widgets are also allowed, such as YouKongregate or Badge Master. There is an increasing amount of Tutorials uploaded to Kongregate, many of them game development tutorials or programming tutorials.