What is 12-factor? 12 Factor is a methodology for building(language agnostic) software-as-a-service apps that: Directly from the manifesto: Use declarative formats for setup automation, to minimize time and cost for new developers joining the project Have a clean contract with the underlying operating system, offering maximum portability between execution environments Are suitable for deployment on modern cloud platforms, obviating the need for servers and systems administration Minimize divergence between development and production, enabling continuous deployment for maximum agility Can scale up without significant changes to tooling, architecture, or development practices.