From 12factor.net:

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