In the modern era, software is commonly delivered as a service: called web apps, or software-as-a-service. The twelve-factor app is a methodology for building software-as-a-service apps that:

* 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;
* And can scale up without significant changes to tooling, architecture, or development practices.

This methodology has been developed from deep experience, and is currently applied at Heroku by both internal apps, and apps customers deploy.

This presentation will provide an overview of the 12 factors, and how they apply to Python applications and the environment you deploy them in to.