The Twelve-Factor App

Codebase: One codebase tracked in revision control, many deploys.

Dependencies: Explicitly declare and isolate dependencies.

Config: Store config in the environment.

Backing services: Treat backing services as attached resources.

Build, release, run: Strictly separate build and run stages.

Processes: Execute the app as one or more stateless processes.

Port binding: Export services via port binding.

Concurrency: Scale out via the process model.

Disposability: Maximize robustness with fast startup and graceful shutdown.

Dev/prod parity: Keep development, staging, and production as similar as possible.

Logs: Treat logs as event streams.

Admin processes: Run admin/management tasks as one-off processes.