The Twelve-Factor App


In the modern era, software is commonly delivered as a service: called web apps, or software-as-a-service. The twelve-factor app is a methodology for building software-as-a-service apps that:

The twelve-factor methodology can be applied to apps written in any programming language, and which use any combination of backing services (database, queue, memory cache, etc).


The contributors to this document have been directly involved in the development and deployment of hundreds of apps, and indirectly witnessed the development, operation, and scaling of hundreds of thousands of apps via our work on the Heroku platform.

This document synthesizes all of our experience and observations on a wide variety of software-as-a-service apps in the wild. It is a triangulation on ideal practices for app development, paying particular attention to the dynamics of the organic growth of an app over time, the dynamics of collaboration between developers working on the app's codebase, and avoiding the cost of software erosion.

Our motivation is to raise awareness of some systemic problems we've seen in modern application development, to provide a shared vocabulary for discussing those problems, and to offer a set of broad conceptual solutions to those problems with accompanying terminology. The format is inspired by Martin Fowler's books Patterns of Enterprise Application Architecture and Refactoring.

Who should read this document?

Any developer building applications which run as a service. Ops engineers who deploy or manage such applications.

The Twelve Factors

I. Código base (Codebase)

Un código base sobre el que hacer el control de versiones y multiples despliegues

II. Dependencias

Declarar y aislar explícitamente las dependencias

III. Configuración

Guardar la configuración en el entorno

IV. Backing services

Tratar a los "backing services" como recursos conectables

V. Construir, distribuir, ejecutar

Separar completamente la etapa de construcción de la etapa de ejecución

VI. Procesos

Ejecutar la aplicación como uno o más procesos sin estado

VII. Asignación de puertos

Publicar servicios mediante asignación de puertos

VIII. Concurrencia

Escalar mediante el modelo de procesos

IX. Disponibilidad

Hacer el sistema más robusto intentando conseguir inicios rápidos y finalizaciones seguras

X. Igualdad entre desarrollo y producción

Mantener desarrollo, preproducción y producción tan parecidos como sea posible

XI. Historiales

Tratar los historiales como una transmisión de eventos

XII. Administración de procesos

Ejecutar las tareas de gestión/administración como procesos que solo se ejecutan una vez