I recently presented on SpiderMonkey and Byte-Sized Architectures at a JSConf.jp/TC39 collaborative meeting the evening before the TC39 plenary in Tokyo. The first part of the presentation is a high-level view of the overall architecture of SpiderMonkey, and gives an idea of how a modern JavaScript engine is put together. In the second part, I talk about bytesize architectures a way for teams to build a shared understanding of complicated systems.