What is the difference between monolithic and microservices architecture?

Question

Accepted Answer

**Monolith** — single deployable unit. **Microservices** — independent services.

**Monolith:**
- Single codebase.
- Single deployment.
- Shared database.
- Simple initially.
- Hard to scale individual parts.

```
Monolith:
[User Module] [Order Module] [Payment Module]
        ↓            ↓             ↓
         [Single Database]
         [Single Deploy]
```

**Microservices:**
- Multiple services.
- Independent deployments.
- Database per service.
- Complex initially.
- Easy to scale individual services.

```
Microservices:
[User Service]  [Order Service]  [Payment Service]
     ↓                ↓                 ↓
  [User DB]       [Order DB]       [Payment DB]
  [Deploy A]      [Deploy B]       [Deploy C]
```

**Key differences:**
- **Monolith** — simple, coupled.
- **Microservices** — complex, decoupled.

Systems Analyst: What is the difference between monolithic and microservices architecture?