Principle: Twelve-Factor App methodology

Applications built without cloud-native principles are hard to deploy, scale, and maintain across environments.

The twelve factors for cloud-native applications:

1. CODEBASE: One codebase tracked in version control, many deploys
2. DEPENDENCIES: Explicitly declare and isolate dependencies
3. CONFIG: Store config in environment variables (not in code)
4. BACKING SERVICES: Treat databases, queues as attached resources
5. BUILD, RELEASE, RUN: Strictly separate build and run stages
6. PROCESSES: Execute app as stateless processes
7. PORT BINDING: Export services via port binding
8. CONCURRENCY: Scale out via the process model
9. DISPOSABILITY: Fast startup and graceful shutdown
10. DEV/PROD PARITY: Keep development and production as similar as possible
11. LOGS: Treat logs as event streams (stdout, not files)
12. ADMIN PROCESSES: Run admin tasks as one-off processes

Most impactful for most teams:

• #3 (Config in env vars) — no secrets in code
• #6 (Stateless) — enables horizontal scaling
• #9 (Disposability) — enables zero-downtime deploys
• #10 (Dev/Prod parity) — use Docker for consistency
• #11 (Logs to stdout) — let the platform handle aggregation

These principles make applications portable across cloud providers, easy to scale, and simple to operate in containerized environments.