This episode is all about Heroku's Twelve Factor applications, which are design rules for building flexible, sustainable and robust cloud-native application. I. Codebase - One codebase tracked in revision control, many deploys II. Dependencies - Explicitly declare and isolate dependencies III. Config - Store config in the environment IV. Backing services - Treat backing services as attached resources V. Build, release, run - Strictly separate build and run stages VI. Processes - Execute the app as one or more stateless processes VII. Port binding - Export services via port binding VIII. Concurrency - Scale out via the process model IX. Disposability - Maximize robustness with fast startup and graceful shutdown X. Dev/prod parity - Keep development, staging, and production as similar as possible XI. Logs - Treat logs as event streams XII. Admin processes - Run admin/management tasks as one-off processes