Software Development Patterns: Separation of Concerns

In 1974, Dijkstra introduced "separation of concerns" as a way to manage complexity in software systems. Nearly 50 years later, we're still debating its implementation - but perhaps we've been looking at it wrong all along.

The Problem with Strict Separation

Throughout my career mentoring engineering teams, I've noticed a pattern: strict separation often leads to fragmented systems that are harder to maintain, not easier. The real power comes from thoughtful orchestration.

The Power of Orchestration

An orchestrator provides clear workflow ownership while maintaining loose coupling. It's not about separating technology layers - it's about organizing around business capabilities.

David Khourshid, creator of XState, puts it perfectly: "The common principle of separation of concerns is often blindly applied and leads to fragile architecture. Orchestration is the missing part."

Event-Based Systems

Event-based systems that work with clear interfaces, hide their complexity and delegate responsibilities through message passing are very powerful.

Think of it like a symphony:

Individual musicians (services) are experts in their instruments
The conductor (orchestrator) creates the harmony
The separation exists naturally through expertise
Orchestration brings purpose and direction

React as a Perfect Example

React is the perfect example: it allows developers to decide how to split the "concern", the context of a feature. One can organize by components, seen as boundaries of cohesive code, regardless of their nature.

With this in mind, a good separation I've seen, is to:

Keep orchestration in routes
Delegate to components only the rendering or interaction logic

Benefits of This Vertical Approach

This vertical approach brings three key benefits I've seen in production:

Routes become natural boundaries for feature modules
State management stays close to where it's needed
Business logic lives with its related components

#microservices #systemdesign #architecture