12 / 15 Factor App

The [12-factor](https://12factor.net/ app methodology, originally developed by Heroku, provides a comprehensive set of best practices for building cloud-native applications. This methodology emphasizes creating applications that are easy to manage, scalable, and portable across different environments. The 15-factor model extends this framework to address additional concerns relevant in modern cloud-native development.

Core Principles of 12-Factor Apps

• Codebase: Maintain a single codebase tracked in version control, with multiple deployments.
• Dependencies: Explicitly declare and isolate dependencies.
• Config: Store configuration 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.

Extending to 15 Factors

The 15-factor model builds upon the original principles by adding:

• API First: Design APIs first to ensure interoperability and future-proofing.
• Telemetry: Implement robust telemetry for monitoring and diagnostics.
• Authentication and Authorization: Incorporate strong, centralized authentication and authorization mechanisms.