Architecture paradigms

When NOT To Use

• The paradigm is already chosen, so go straight to that paradigm's skill
• Reviewing an existing design against its ADRs (use pensive:architecture-review)

Table of Contents

• Quick Scenario Router
• 3-Step Selection Workflow
• Available Paradigm Skills
• Integration with Other Skills
• Exit Criteria

Architecture Paradigm Router

This skill helps you select the right architecture paradigm(s) for your system, then routes you to the specific paradigm skill for implementation details.

Quick Scenario Router

Match your needs to the recommended paradigm:

Your Scenario	Primary Paradigm	Load Skill
Enterprise app with multiple teams	Microservices or Modular Monolith	architecture-paradigm-microservices or architecture-paradigm-modular-monolith
Complex business rules & testing	Functional Core, Imperative Shell	architecture-paradigm-functional-core
Real-time/event processing	Event-Driven Architecture	architecture-paradigm-event-driven
Legacy system modernization	Hexagonal (Ports & Adapters)	architecture-paradigm-hexagonal
Cloud-native/bursty workloads	Serverless	architecture-paradigm-serverless
ETL/data processing pipeline	Pipeline Architecture	architecture-paradigm-pipeline
Simple CRUD app	Layered Architecture	architecture-paradigm-layered
Command/query separation	CQRS and Event Sourcing	architecture-paradigm-cqrs-es
Rich business rules to model	Domain-Driven Design	architecture-paradigm-domain-driven

One of these is not like the others. Domain-Driven Design answers "what are the concepts and what do we call them." The rest answer "where does the code go." DDD composes with a structural paradigm (commonly layered, hexagonal, or modular monolith) rather than competing with it, so selecting it does not mean deselecting one of the others.

3-Step Selection Workflow

Step 1: Define Your Needs

Primary Concerns (select all that apply):

• Testability: Isolate business logic → functional-core or hexagonal
• Team Autonomy: Independent deployment → microservices or modular-monolith
• Infrastructure Flexibility: Swap databases/frameworks → hexagonal
• Real-time Scaling: Variable loads with events → event-driven or space-based
• Simplicity: Maintainable without complexity → layered or modular-monolith
• Legacy Integration: Work with existing systems → hexagonal or microkernel

System Context:

• Team Size: < 5 → Layered/Functional Core | 5-15 → Modular Monolith | 15-50 → Microservices | 50+ → Microservices/Space-Based
• Domain Complexity: Simple → Layered | Moderate → Hexagonal/Modular Monolith | Complex → Functional Core/CQRS | Highly Complex → Microservices/Event-Driven

Step 2: Evaluate Paradigms

Based on your needs from Step 1, review these options:

For Testability & Business Logic

• Load architecture-paradigm-functional-core - Isolates business logic from infrastructure
• Load architecture-paradigm-hexagonal - Clear domain/infrastructure boundaries

For Team Autonomy

• Load architecture-paradigm-microservices - Independent deployment and scaling
• Load architecture-paradigm-modular-monolith - Team autonomy without distributed complexity

For Infrastructure Flexibility

• Load architecture-paradigm-hexagonal - Swap infrastructure without domain changes

For Simplicity & Maintainability

• Load architecture-paradigm-layered - Simple, well-understood separation

For Rich Business Rules

• Load architecture-paradigm-domain-driven - Models the business in its own language. Pair it with whichever structural paradigm you picked above; it does not replace one. Skip it when the domain is CRUD over a form, where the model would just be the schema under a new name.

For Real-time Event Processing

• Load architecture-paradigm-event-driven - Scalable, decoupled processing
• Load architecture-paradigm-space-based - In-memory data grids for linear scalability

For Legacy Integration

• Load architecture-paradigm-microkernel - Plugin architecture for extensible platforms
• Load architecture-paradigm-hexagonal - Adapters for external systems

Step 3: Load Paradigm Skill for Implementation

Once you've selected your paradigm(s), load the specific skill for detailed guidance:

# Example: You selected Hexagonal Architecture
Skill(archetypes:architecture-paradigm-hexagonal)

The individual paradigm skill provides:

• ✅ Complete implementation guide
• ✅ ADR templates
• ✅ Migration checklist
• ✅ Code examples
• ✅ Testing strategies
• ✅ Risk assessments

Available Paradigm Skills

Paradigm	Complexity	Team Size	Best For	Skill Name
Functional Core	Medium	Small-Large	Complex business logic	architecture-paradigm-functional-core
Hexagonal	Medium	Small-Large	Infrastructure changes	architecture-paradigm-hexagonal
Layered	Low	Small-Medium	Simple domains	architecture-paradigm-layered
Modular Monolith	Medium	Medium-Large	Evolving systems	architecture-paradigm-modular-monolith
Microservices	High	Large	Complex domains	architecture-paradigm-microservices
Event-Driven	High	Medium-Large	Real-time processing	architecture-paradigm-event-driven
CQRS and ES	High	Medium-Large	Audit trails	architecture-paradigm-cqrs-es
Service-Based	Medium	Medium	Coarse-grained services	architecture-paradigm-service-based
Serverless	Medium	Small-Medium	Cloud-native/bursty	architecture-paradigm-serverless
Microkernel	Medium	Small-Medium	Plugin systems	architecture-paradigm-microkernel
Space-Based	High	Large	Linear scalability	architecture-paradigm-space-based
Pipeline	Low	Small-Medium	ETL workflows	architecture-paradigm-pipeline
Client-Server	Low	Small	Traditional apps	architecture-paradigm-client-server
Domain-Driven Design	Medium	Small-Large	Rich business rules (composes with the above)	architecture-paradigm-domain-driven

Integration with Other Skills

• Architecture Review: Use this skill first to select paradigms, then /architecture-review for evaluation
• Implementation Planning: Select paradigms here, then /writing-plans for detailed task breakdown
• Refactoring: Identify target paradigms here, then use paradigm-specific skills for migration strategies

Exit Criteria

• At least one paradigm is selected with clear rationale
• Specific paradigm skill has been loaded for detailed guidance
• Ready to create ADR or implementation plan

Next Steps

1. Load the specific paradigm skill - Use Skill(archetypes:architecture-paradigm-NAME)
2. Generate an ADR - Use the paradigm's ADR templates
3. Create implementation plan - Use paradigm's migration checklist
4. Set up monitoring - Track success metrics from paradigm guidance