The Twelve Factor App is a methodology used for building software-as-a-service applications. The methodology consists of twelve different factors, which when implemented correctly, result in an extendable, deployable, maintainable and scalable application.
The Twelve Factors
as per 12factor.net.
One codebase tracked in revision control, many deploys
Explicitly declare and isolate dependencies
Store config in the environment
Treat backing services as attached resources
Build, release, run
Strictly separate build and run stages
Execute the app as one or more stateless processes
Export services via port binding
Scale out via the process model
Maximize robustness with fast startup and graceful shutdown
Keep development, staging, and production as similar as possible
Treat logs as event streams
Run admin/management tasks as one-off processes