McAlpin began posting "Multiplex" in July 2005. His brother Lawrence, a programmer, helped set up the website for him and later programmed the "Multiplex" iPhone app. When McAlpin began writing his webcomic, he liberally made use of the dynamic canvas size of webcomics, making his strips as long as they needed to be. McAlpin originally intended to create "Multiplex" as an animated short, but abandoned the idea and later decided to publish it as a webcomic. Visually, McAlpin was strongly influenced by cut paper animation and vector graphics, stating that "the flatness of it can be beautiful thing." The writing of "Multiplex" was inspired by "Archie", "South Park", "Clone High", and sitcoms like "The Office" and "It's Always Sunny in Philadelphia".