The Fifteen-Factor App methodology for modern cloud-native SaaS applications. This skill should be automatically invoked when planning SaaS tools, product software architecture, microservices design, PRPs/PRDs, or cloud-native application development. Extends the original Twelve-Factor App principles with three additional factors (API First, Telemetry, Security). Trigger keywords include "fifteen factor", "12 factor", "SaaS architecture", "cloud-native design", "application architecture", "microservices best practices", or when in a planning/architecture session.
View on GitHubhenkisdabro/wookstar-claude-plugins
developer
February 1, 2026
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npx add-skill https://github.com/henkisdabro/wookstar-claude-plugins/blob/main/plugins/developer/skills/fifteen-factor-app/SKILL.md -a claude-code --skill fifteen-factor-appInstallation paths:
.claude/skills/fifteen-factor-app/# Fifteen-Factor App Methodology ## Overview The Fifteen-Factor App methodology extends the original Twelve-Factor App principles (created by Heroku in 2012) with three additional factors essential for modern cloud-native applications: API First, Telemetry, and Security. This methodology provides architectural principles and guidelines for building software-as-a-service applications that are: - **Performant** - Optimised for speed and efficiency - **Scalable** - Designed for horizontal scaling without significant changes - **Manageable** - Easy to deploy, monitor, and maintain - **Resilient** - Robust against failures with graceful degradation ## When to Apply This Methodology Apply the Fifteen-Factor principles during: 1. **Architecture Planning** - When designing new applications or microservices 2. **PRP/PRD Creation** - When documenting technical requirements and specifications 3. **Code Reviews** - When evaluating whether implementations follow best practices 4. **Migration Planning** - When modernising legacy applications for cloud deployment 5. **Technical Debt Assessment** - When identifying architectural improvements ## The Fifteen Factors at a Glance | Factor | Principle | Key Concept | |--------|-----------|-------------| | I. Codebase | One codebase, many deploys | Single repo per app, version controlled | | II. Dependencies | Explicitly declare and isolate | No implicit system-wide packages | | III. Config | Store in environment | Never hardcode configuration | | IV. Backing Services | Treat as attached resources | Databases, caches are swappable resources | | V. Build, Release, Run | Strict separation | Immutable releases, no runtime changes | | VI. Processes | Stateless and share-nothing | Horizontal scaling, no sticky sessions | | VII. Port Binding | Export via port | Self-contained, no runtime injection | | VIII. Concurrency | Scale out via process model | Horizontal over vertical scaling | | IX. Disposability | Fast startup, graceful shutd