Your project is significantly more complex than an 'ordinary SaaS'. My own canonical example of a SaaS would be something like WuFoo, or Squarespace. These are characterized as pure webapp component producing technologies, from soup to nuts, with through-the-web tooling for everything from specializing your components, to managing your payment details. The system is "closed" in the sense that it only produces and consumes web components for all operations. There is no real-world device that is critical to operation - so you are free to run services like these on any device, or collection of devices, as long as its users can find 'a useful stateful service' at 'name'. For your project, this is only the first foundational requirement.