Twelve-Factor App -- cloud-native application methodology

Applications deployed to cloud platforms face issues with configuration, dependencies, logging, and scaling because they were designed for traditional server environments.

Follow the twelve-factor methodology: (1) Codebase: one repo per app. (2) Dependencies: explicitly declare and isolate. (3) Config: store in env vars, not code. (4) Backing services: treat as attached resources. (5) Build/release/run: strict separation. (6) Processes: stateless, share-nothing. (7) Port binding: self-contained, export via port. (8) Concurrency: scale via process model. (9) Disposability: fast startup, graceful shutdown. (10) Dev/prod parity: keep environments similar. (11) Logs: treat as event streams. (12) Admin processes: run as one-off processes.

Cloud platforms (Heroku, AWS, GCP, Kubernetes) assume these patterns. Violating them causes deployment failures, scaling issues, and operational burden.