Twelve-Factor App
12 principer för cloud-native applikationer. Adam Wiggins (Heroku co-founder), 2011. Bibel för moderna webapp-design: stateless processes, config i env vars, dev/prod parity.
De 12: Codebase, Dependencies, Config, Backing services, Build/release/run, Processes, Port binding, Concurrency, Disposability, Dev/prod parity, Logs, Admin processes. Skapad för Heroku-eran men har överlevt — alla container/Kubernetes-best-practices följer 12-factor. Modernt tillägg: 15-factor (Pivotal/VMware, lade till API first, telemetry, authentication). Konflikter med modernt: "stateless processes" passar inte WebSocket/realtime; "logs as event streams" var pre-OpenTelemetry.