In years past building Visual Studio Extensions have often been considered the realm of the big boys. Staff working at Jetbrains or the Microsoft employees of the world. Last year I saw a talk given by Mads Kristensen aimed at taking away some of this stigma and showing how easy the guys at Microsoft have tried to make it for developers like you and me to just up and write extensions. I’ve been wanting to build one ever since, but haven’t had a good enough excuse to jump right in – until now. Here follows the creation of “OnCheckin Web.config Transformer”.