The verdict in three sentences
Microservices only make sense beyond a certain threshold: a team of 15-20 developers, high traffic, a need for autonomous squads. Below that, the modular monolith is faster to ship, cheaper to operate and far simpler to debug. In London in 2026, moving to microservices adds 20 to 40 % upfront cost and 800 to 3,000 EUR/month of infrastructure — an investment justified only when scale demands it.
The real cost of microservices
Splitting into independent services is appealing on paper: scalability, isolated deployments, resilience. But each service adds plumbing: networking, observability, orchestration, distributed failure handling.
| Item | Modular monolith | Microservices |
|---|---|---|
| Upfront dev overhead | Baseline | +20-40 % |
| Infra/month 2026 | 200-800 EUR | 800-3,000 EUR |
| Delivery timeline | Baseline | +2-4 months |
| Ops complexity | Low | High (K8s, CI/CD) |
| Debugging | Simple (1 process) | Distributed, tracing required |
| Deployment | Global | Per service, independent |
| Minimum effective team | 2-10 devs | 15-20+ devs |
The classic trap: a 4-developer SME adopts microservices "to be scalable", ends up with 12 services, a tripled cloud bill and bugs impossible to trace. The scalability it needed fit inside a well-partitioned monolith.
Decision grid for your context
The right question is not "micro or monolith" but "at what threshold do we switch". Here are the criteria we weigh.
| Criterion | Stay monolith | Go microservices |
|---|---|---|
| Dev team size | < 15 | > 15-20 |
| Traffic | < 10k req/min | > 50k req/min |
| Business domains | 1-3 | 5+ decoupled |
| Need for isolated deploys | No | Yes, critical |
| Infra budget/month | < 800 EUR | > 800 EUR accepted |
| DevOps maturity | Beginner/mid | High |
The most cost-effective middle path in 2026: the modular monolith. One deployment, but modules with clean boundaries you can extract into services the day scale requires it. You keep today's simplicity and tomorrow's microservices option.
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Mini case study
Julian, CTO of a SaaS scale-up in London, 9 developers, considers microservices "before it's too late". Microservices estimate: +35 % dev on a 180,000 EUR project (i.e. +63,000 EUR) and 2,400 EUR/month infra. With only 9 devs and 8,000 req/min, he opts for a modular monolith: 600 EUR/month infra, delivery 3 months earlier. Over 18 months he saves 63,000 EUR dev + 32,400 EUR infra, while keeping the architecture ready to be split once the team passes 15 people.
FAQ
How many developers justify microservices? Generally beyond 15 to 20 developers organized into autonomous squads. Below that, cross-service coordination costs more than it returns.
What does microservices infrastructure cost per month? Budget 800 to 3,000 EUR/month in 2026 (Kubernetes orchestration, observability, multiple databases), versus 200 to 800 EUR for an equivalent monolith.
What is a modular monolith? A single deployable application, but organized into modules with strict boundaries. You keep operational simplicity while being able to extract a module into a microservice later, without a full rewrite.
Do microservices really improve scalability? Yes, but only for high loads (> 50k req/min) or spikes targeted at one service. For moderate traffic, a well-optimized monolith scales horizontally very well.
How much delay do microservices add? About 2 to 4 months on the initial project, to set up CI/CD, observability and distributed failure handling.
Let's scope your project. Give us your team size, traffic and business domains, and we will recommend a modular monolith or microservices with a costed infra budget. 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.
