Architecture Decision Framework
"Requirements drive architecture. Trade-offs inform decisions. ADRs capture rationale."
Core Principle
"Simplicity is the ultimate sophistication."
- •Start simple
- •Add complexity ONLY when proven necessary
- •You can always add patterns later
- •Removing complexity is MUCH harder than adding it
Decision Process
1. Understand Requirements
| Question | Purpose |
|---|---|
| What problem are we solving? | Core need |
| Who are the users? | Scale, patterns |
| What are the constraints? | Time, budget, team |
| What must it integrate with? | Dependencies |
2. Evaluate Trade-offs
Every decision has costs:
| Choice | Benefits | Costs |
|---|---|---|
| Microservices | Scale, team autonomy | Complexity, latency |
| Monolith | Simple, fast | Scaling limits |
| Event-driven | Decoupling | Debugging harder |
| Sync calls | Simple to reason | Coupling, blocking |
3. Document Decisions (ADR)
markdown
# ADR-001: [Decision Title] ## Status Accepted / Proposed / Deprecated ## Context What is the issue we're facing? ## Decision What we decided to do. ## Consequences What are the results, both positive and negative?
Pattern Selection
When to Use What
| Pattern | Use When | Avoid When |
|---|---|---|
| Singleton | Single instance needed globally | Testing is priority |
| Observer | Many listeners, loose coupling | Simple direct calls work |
| Factory | Complex object creation | Constructor is sufficient |
| Strategy | Interchangeable algorithms | Single implementation |
| State Machine | Clear state transitions | States are ambiguous |
Anti-Patterns
| ❌ Pattern | Problem |
|---|---|
| Big Ball of Mud | No structure, everything coupled |
| Golden Hammer | Using one solution for everything |
| Premature Abstraction | Abstracting before understanding |
| Cargo Cult | Copying patterns without understanding |
Validation Checklist
Before finalizing architecture:
- • Requirements clearly understood
- • Constraints identified
- • Each decision has trade-off analysis
- • Simpler alternatives considered
- • ADRs written for significant decisions
- • Team expertise matches chosen patterns
The best architecture is the simplest one that meets all requirements.