The verdict in three sentences
For a business app in Amsterdam, the modular monolith remains the best default: cheaper, faster to ship, simpler to operate. Microservices cost 30 to 60% more in development, add 4 to 8 weeks of delay and 900 to 2,500 EUR/month of infrastructure, versus 400 to 900 EUR for a monolith. They are only justified beyond a clear break-even point: heavy load, multiple teams, the need to deploy modules independently.
The real cost gap
The microservices premium is not just a dev line item: it is paid in infrastructure, tooling and operational skills. Here is the 2026 ballpark for a mid-sized business app.
| Item | Modular monolith | Microservices |
|---|---|---|
| Initial dev cost | 45,000 - 80,000 EUR | 65,000 - 128,000 EUR |
| Delivery time | Baseline | +4 to +8 wks |
| Monthly infra | 400 - 900 EUR | 900 - 2,500 EUR |
| Tooling (CI/CD, observability) | 100 - 300 EUR/mo | 400 - 1,200 EUR/mo |
| Skills required | 2 - 3 profiles | 4 - 6 profiles |
| 3-year TCO (ballpark) | 70,000 - 130,000 EUR | 130,000 - 260,000 EUR |
The 30 to 60% dev premium comes mainly from inter-service coordination, internal API contracts and distributed data management.
Decision criteria by project size
The choice is not about fashion but measurable criteria. This table summarizes when each architecture takes the lead.
| Criterion | Favors monolith | Favors microservices |
|---|---|---|
| Team | 1 to 8 developers | 3+ autonomous teams |
| Traffic / load | Predictable, moderate | Heavy, spiky, uneven |
| Deployment cadence | Weekly | Several times/day |
| Functional domains | Coupled | Clearly decoupled |
| Monthly infra budget | < 900 EUR | > 900 EUR accepted |
| DevOps maturity | Beginner to medium | High |
Recommendation by size: under 80,000 EUR budget with a single team, stay on a well-structured modular monolith (you can extract services later). Beyond that, with multiple teams and differentiated scalability needs, microservices become worthwhile.
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Mini case study
Sarah, COO of an industrial firm in Amsterdam, wants to rebuild her business app and her vendor proposes microservices upfront. The quote jumps from 58,000 EUR (modular monolith) to 92,000 EUR, with infra climbing from 600 to 1,900 EUR/month. Her real traffic: ~200 internal users, controlled peaks. Over 3 years, the cumulative gap exceeds 80,000 EUR for near-zero scalability need. She picks a modular monolith with clean module boundaries: delivery 6 weeks sooner, and the option to extract a service later if load demands it.
FAQ
Are microservices always more scalable? Not necessarily. A well-designed monolith handles heavy loads via horizontal scaling. Microservices shine mainly when modules must scale independently of one another.
Can we migrate from a monolith to microservices later? Yes, it is the recommended path: start with a modular monolith, then extract the services that justify it. This avoids paying for complexity before you need it.
What is the real hidden cost of microservices? Operations: observability, CI/CD, distributed failure handling and DevOps skills. Budget 400 to 1,200 EUR/month of extra tooling, before servers.
At what traffic do microservices pay off? There is no universal threshold, but rarely below several thousand active users or without multiple teams. Below that, the monolith offers a better cost/value ratio.
How much extra delay for microservices? Budget 4 to 8 additional weeks on a mid-sized project, the time to set up infrastructure, API contracts and observability.
Let's scope your project. Give us your target traffic, team size and growth horizon, and we'll recommend the architecture at the right cost, without over-engineering. Detailed quote within 48 h. WhatsApp +221 77 596 93 33.
Mohamed Bah
Fondateur, Kolonell
Passionate about digital and entrepreneurship in Africa, Mohamed has been helping Sénégalese businesses with their digital transformation since 2020. Founder of Kolonell, he believes every SME deserves a professional and accessible online présence.
