Monolithic vs Microservices: Which Architecture Should You Choose?

One of the hottest debates in the software world: monolithic or microservices? The truth is, both are correct — in the right context.

What Is Monolithic Architecture?

In a monolithic architecture, the entire application is developed, deployed, and run as a single unit.

Advantages

• Simple development — Single codebase, single IDE
• Easy debugging — All code in one place
• Simple deployment — Deploy a single artifact
• Lower cost — Minimal infrastructure requirements
• ACID transactions — Easy within a single database

Disadvantages

• Scaling difficulty — Entire application must scale together
• Technology lock-in — Single language/framework constraint
• Growing codebase — Becomes complex over time
• Deployment risk — Small changes affect the entire application
• Team bottleneck — Large teams face merge conflicts

What Is Microservices Architecture?

In microservices, the application is split into small, independent services, each with its own database.

Advantages

• Independent deployment — Each service deploys separately
• Technology diversity — Each service can use different languages
• Independent scaling — Only scale the busy service
• Team autonomy — Each team owns their service
• Fault isolation — One service crash doesn't affect others

Disadvantages

• Distributed system complexity — Network failures, latency
• Data consistency — Eventual consistency instead of ACID
• Operational overhead — Monitoring, logging, service mesh
• Debugging difficulty — Errors may span multiple services
• Cost — More infrastructure, more DevOps effort

Decision Framework

Choose Monolithic When:

• ✅ Small team (1-5 people)
• ✅ New project / MVP / startup
• ✅ Simple domain
• ✅ Limited DevOps experience
• ✅ Speed of iteration is the priority

Choose Microservices When:

• ✅ Large team (10+ people)
• ✅ Mature project with proven business model
• ✅ Different scaling requirements
• ✅ Strong DevOps culture
• ✅ Independent deployment is essential

The Third Way: Modular Monolith

An approach that preserves the simplicity of monolithic architecture while gaining the advantages of modularity:

┌─────────────────────────────────┐
│        MODULAR MONOLITH         │
│  ┌─────────┐   ┌─────────┐     │
│  │ Module A │   │ Module B │    │
│  │ (own     │   │ (own     │    │
│  │  API)    │   │  API)    │    │
│  └─────────┘   └─────────┘     │
│        SHARED DATABASE          │
└─────────────────────────────────┘

At BilgeOne, we use this approach. Each industry vertical (restaurant, hotel, retail) is designed as a module. If needed, any module can be extracted into an independent service later.

Real-World Examples

| Company | Started | Transitioned | Result | |---------|---------|-------------|--------| | Netflix | Monolithic | → Microservices | 1000+ services | | Amazon | Monolithic | → Microservices | SOA → Microservices | | Shopify | Modular Monolith | Stayed monolith | Ruby on Rails | | Basecamp | Monolithic | Stayed monolith | "Majestic Monolith" |

Conclusion

The right architecture depends on your project's context. Start monolithic for speed, modularize as you grow, and only split into microservices when truly needed.

"Start monolithic, modularize, then split into services when required. Don't skip steps." — F. Çağrı Bilgehan

Practice these architectural decisions interactively on LabLudus.