Software architecture
Microservices architecture for companies in Spain: when it's worth it and when it's not
Published: February 19, 2026
Microservices solve real problems around scale, team autonomy, and independent deployment. They also multiply operational complexity, infrastructure costs, and development time. Adopting them too early is one of the most expensive mistakes in enterprise software projects.
This guide targets CTOs, software architects, and technology directors at Spanish companies evaluating whether to migrate to microservices or start a new project with this architecture. If your team has fewer than 20 engineers and your product is under 3 years old, a well-designed modular monolith is probably the smartest decision.
When microservices actually make sense
- You have teams of 8-10+ engineers working in parallel on different domains: independent deployment reduces blocking.
- You need to scale specific components independently (payments service has 10x more load than users service).
- Your roadmap requires different parts of the system to evolve at different speeds.
- You have operational maturity: solid CI/CD, observability, secrets management, and container orchestration all working.
The operational cost nobody mentions in the pitch
- Network latency: each inter-service call adds latency. In high-frequency synchronous flows, this compounds.
- Observability complexity: distributed tracing, log correlation, and distributed alerting are much more expensive to operate.
- Eventual consistency: transactions that were local are now distributed. Saga pattern, compensating transactions, and more.
- Team overhead: each service needs its own CI/CD, tests, API documentation, and oncall rotation.
Modular monolith vs microservices: an honest comparison
- Well-structured modular monolith: 90% of microservices benefits, 20% of operational complexity.
- Right for: teams up to 15 engineers, products in early-growth phase, domains not yet fully defined.
- Microservices right for: mature products with clear domains, large teams, need for granular scaling.
- Most mid-sized Spanish companies are in the modular monolith range. Microservices come later.
How to migrate from monolith to microservices without breaking operations
- Strangler fig pattern: extract services from the monolith incrementally from the edges, no big-bang rewrite.
- Start with the domain under highest load or most frequent change: maximum impact, minimum coupling risk.
- Define API contracts before separating: the contract is the service boundary, not the technology.
- Don't extract a service until the domain is fully understood: refactors in microservices are expensive.
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