Tornado is a lean web framework. Vague, yes. Allow me to explain. Tornado doesn't get in the way of the developer trying to build an application by imposing too many conventional constraints. Each web framework that gets put out there in the community, be it Python or otherwise, adopts its own conventions. Usually from inception onward. Conventions establish a standard set of practices, patterns — call them what you will — they're essentially rules that explain how to best utilize the framework because some other developer had done it that way before. By and large, this approach works. Develop a toolkit that has a vast collection of reusable components and an instruction manual on how to use them in isolation as well as building new, larger components from smaller ones. By following these conventions on how to get the most reuse out of these parts, the developer really only needs to tap their previous project experience with similar code and the rest should just fall into place — assuming they've read all the documentation and learn how to follow the patterns of the framework very quickly.