If you've ever thought about splitting your large software application into microservices, you're not alone. The hype around microservices is still huge. "Better scalability!", "More independence of teams!", "Technology diversity!" – that all sounds pretty good, doesn't it? But if you dive deeper into a real project, you'll quickly realise that the reality is much more complex. In this article, we'll look at what really matters when it comes to microservices. No theory, no buzzwords, but real learnings from practice.
What microservices promise in theory
In theory, microservices are about breaking down a large software application into small, independent services. Each of these services is responsible for exactly one specialist area and communicates with others via clearly defined interfaces. In the best case, these services can be developed, tested, deployed and scaled independently of each other. This promises more flexibility, better maintainability and an organisation that is better suited to distributed teams.
In practice, however, the situation is often quite different.
Boundaries and stumbling blocks from real projects
Distributed systems are inherently complex
The first big disillusionment usually comes quickly: You are suddenly no longer dealing with one system, but with ten, twenty or more. Communication takes place over the network, which means you have to be prepared for timeouts, latency and partial failures. Every new service-to-service conversation is a potential point of failure. You need central monitoring and logging solutions to be able to understand what's going wrong and when, where.
Data storage is becoming a challenge
„Every service needs its own database" – that's what it says in many architecture books. And yes, there are good reasons for this: it promotes independence and isolation. But in practice? Many domains are not really isolated from each other. Data must be kept synchronous, and dependencies arise due to shared IDs, events or even inconsistent states. Eventual consistency sounds okay in theory, but if your customer suddenly sees a payment status that doesn't match their order, it quickly becomes uncomfortable.
The overhead should not be underestimated
What was a simple method for a software application is often an API in a microservice environment. And that means: versioning, authentication, documentation, tests, monitoring. The effort for each feature increases. What's more, if you have your own repo, deployment, and pipelines for each service, your team will need to invest heavily in DevOps, CI/CD, and automation. Otherwise, every release will be a nightmare.
Teams need different skills
Developers who have found their way around a software application are often stuck in a microservice setup. Suddenly, you need to know more about networking, APIs, infrastructure, and deployment. That means training, mentoring, and a lot more communication. Team boundaries are also becoming more important: Who is responsible for which service? Who talks to whom when something doesn't work?
ROI isn't always there
Switching to microservices is not an end in itself. There are many systems where a well-structured software application with modules, clear architecture and automated tests is completely sufficient. Microservices are worthwhile when scaling, independence and release frequency are business-critical. If you don't know exactly why you need them, you probably don't need them (yet).
What really counts in practice
Central logging and monitoring solutions
You need a place where all the logs converge. Whether that's ELK, Loki+Grafana or a cloud service like Datadog is secondary. The important thing is that you have to be able to recognise correlations. If a request travels through five services, you need tracing and correlated IDs. This is the only way you can really narrow down sources of error.
Clear service boundaries and ownership
A microservice that is not autonomous is not a microservice. Keep your boundaries so that services can be deployed and tested independently. Every service should belong to a team that takes responsibility – both professionally and technically. "Shared ownership" sounds good, but it often leads to dilution of responsibilities.
Hard test contracts and interfaces
You need tests that secure your interfaces. Contract tests (e.g. with Pact) help to avoid API incompatibilities. Version your APIs cleanly and document them with OpenAPI/Swagger so that other teams can rely on them.
Automation at all levels
Without a strong CI/CD pipeline, you'll suffocate under the complexity. Automate testing, linting, deployments, rollbacks, and staging environments. Tools like GitHub Actions, GitLab CI, ArgoCD or Jenkins X help you get a grip on the process.
Using asynchronous communication sensibly
Not everything has to be synchronous. Use messaging systems such as Kafka, RabbitMQ or NATS to enable loose coupling. Events can decouple services from each other, but they also come with their own challenges: You need idempotent handlers, retention strategies, and monitoring for event flows.
Errors and timeouts are not the exception, but the rule
Build in resilience: Retries with backoff, circuit breakers, timeouts, fallbacks. Use libraries such as Hystrix, Resilience4j or your own patterns to deal with errors before they hit your customer. Chaos engineering can help you discover vulnerabilities in advance.
Conclusion: Microservices are a tool, not a goal
Microservices offer many benefits – but they come at a price. If you choose architecture because you can solve concrete problems with it, that's great. But simply jumping on the bandwagon because "everyone is doing it" often ends in frustration, extra work and confusing system landscapes.
In everyday life, perfect patterns and purist principles are less important than pragmatic solutions. Build an ecosystem that dominates your team. Focus on good observability, clear responsibilities, and solid automation. And remember: Even a large software application can be clean, maintainable and successful. Microservices are not a promise of salvation – but with the right setup they are a powerful tool.