In late 2009 a game development competition called Assemblee began on the TIGSource forums. The competition was broken into two parts:
Many games were made for this competition using these free non-commercial resources. You’ll find some of these still out there today. WildShadow purchased commercial licenses for the works they used and continued working on the game long after the competition was over. Read more about it from Alex himself, here.
Programming information (from Amitp):
On June 20, 2011 Realm of the Mad God was released on the Chrome Web Store. This was the first time RotMG was made available outside of the official, original website.
On October 31, 2011 the game was released on Kongregate.
On February 20, 2012 the game was released on Steam.
WildShadow announced on June 18, 2012 that they had been acquired by Kabam. Alex and Rob both departed to explore new challenges while Willem remained with Kabam and continued developing new content until his departure on June 21, 2013.
Kabam announced on June 23, 2016 that Realm of the Mad God was being “transferred” to Deca Games. At the same time Deca Games posted a more detailed announcement on their blog. The game officially re-launched under Deca’s complete control on July 21, 2016.
Because Adobe will no longer support Adobe Flash, the existing engine of RotMG, the game will be ported to the Unity engine in 2020. The “remastered” version is called Realm of the Mad God Exalt.