Microservices vs Monolith: Making the Right Choice

The Microservices Hype

Microservices became the default recommendation, but they solve specific problems at a cost. For most teams and projects, a well-structured monolith is more appropriate and productive.

When Monoliths Excel

• Small to medium teams (< 50 developers)
• New projects without clear domain boundaries
• Simple deployment requirements
• Tight deadlines and limited ops capacity

// A modular monolith provides isolation without distributed complexity
app/
├── Modules/
│   ├── Catalog/
│   │   ├── Controllers/
│   │   ├── Models/
│   │   ├── Services/
│   │   └── routes.php
│   ├── Orders/
│   ├── Inventory/
│   └── Shipping/
├── Shared/
│   ├── Events/
│   └── Services/

When Microservices Make Sense

• Large teams needing independent deployment
• Different scaling requirements per component
• Technology diversity needs
• Clear, stable domain boundaries

The Hidden Costs of Microservices

Operational Complexity

// Monolith: One deployment
git push && deploy

// Microservices: Orchestrated deployments
// - Service discovery
// - Load balancing
// - Health checks
// - Circuit breakers
// - Distributed tracing
// - Log aggregation

Data Consistency

// Monolith: ACID transactions
DB::transaction(function () {
    $order = Order::create($data);
    Inventory::decrement($items);
    Payment::charge($total);
});

// Microservices: Eventual consistency, sagas
// Much more complex to get right

Development Experience

// Monolith: Simple local development
php artisan serve

// Microservices: Container orchestration
docker-compose up -d service1 service2 service3 database cache queue

The Modular Monolith Approach

// Module boundaries without network calls
class OrderService
{
    public function __construct(
        private InventoryModule $inventory,
        private PaymentModule $payments
    ) {}

    public function placeOrder(OrderRequest $request): Order
    {
        // In-process calls, can be extracted later
        $this->inventory->reserve($request->items);
        $this->payments->charge($request->total);
        return Order::create($request->toArray());
    }
}

Conclusion

Start with a modular monolith. Extract services only when you have clear domain boundaries and scaling requirements that justify the operational complexity. Most teams never need microservices.