We have been observing for several years that more and more mid-sized companies are questioning their old, monolithic applications and engaging more intensively with the switch to microservices. This step — the transition from monolith to microservices — is usually driven by rising maintenance costs, growing security risks, and the increasing skills shortage. At the same time, expectations of high flexibility and faster deployments are rising. According to our experience, a look at microservices architecture is worthwhile for many businesses that want to modernize their legacy systems in order to remain competitive in the long term.

Why Switch from Monolith to Microservices?

In a monolith, the entire code is bundled into a single, tightly coupled application. All components — from the user interface to database access and business logic — are united in a single software package. This makes changes to individual functional areas more difficult, since every update can affect the entire system. Traditionally, this approach was sufficient for a long time. But in a world where companies have to make rapid adjustments and where, especially in the German mid-market, replacing legacy systems often incurs considerable costs, large monolithic systems are increasingly becoming an obstacle.

Microservices promise more autonomy for individual software building blocks. Each service runs independently and can be maintained by a separate team. This increases agility, reduces failure risks, and enables companies to deliver new functions step by step or to scale selectively. According to GitLab, this decoupled architecture is particularly advantageous for seasonal peaks, since individual services can be scaled up or down independently [1]. The risk that an outage directly paralyzes the entire system thus decreases. These properties are particularly important for B2B companies that have to guarantee reliable services even at peak times such as trade fair phases or year-end business.

The Strategic Advantages of a Microservices Architecture

Looking more closely at the current demands of IT modernization and modernizing legacy systems, it stands out that microservices play to their strengths exactly where monolithic solutions reach their limits:

1. Agility and shorter development cycles: Since each service exists in its own code base, teams can implement changes independently of one another. New features can be rolled out in a targeted manner without potentially uninvolved parts of the application being affected. Development teams can use different programming languages, which increases technological diversity and deploys specialists optimally [1].

2. Scalability: If a company needs high-performance processing for product catalog search, we only scale the responsible microservice. With a monolith, by contrast, we would have to spin up the entire application, even though only one module needs higher computing power. Thanks to microservices, costs can thus be reduced and resources used more deliberately.

3. Independent deployments: When new functions are to be released or security updates applied, each team can version and deploy the respective service independently. Time-to-market is thus accelerated and the risk of large "Big Bang releases" reduced [2].

4. Increased fail-safety: Microservices improve fault tolerance, according to GeeksforGeeks, since a single service is less likely to endanger the entire system in the event of an error [3]. This is particularly significant for B2B companies that have to offer 24/7 operations and service guarantees, for example in sensitive supply chains.

5. Technological flexibility: When a particular service especially benefits from a particular technology — for example because a data analytics application thrives on Python tools — that service can run separately from other technologies. For us, this means: we can choose our technology stack optimally and thus integrate innovations more easily.

Taken together, these advantages secure increased competitiveness, especially when companies want to consistently implement their modernization strategies for legacy software. At the same time, however, we must also be aware that this architectural change is not a pure "plug-and-play" process but a comprehensive rebuild that involves the entire organization.

When Is the Architectural Change Worthwhile?

Before taking the step toward microservices, the question always arises under what conditions the effort actually pays off. Typical triggers are:

• Rising maintenance costs: Monoliths often prove costly as they age. Individual components hang together in complex dependencies, making updates more laborious. Anyone wanting to reduce maintenance costs of legacy systems can therefore benefit from a microservices architecture.

• Security risks: Old frameworks or programming languages can have security vulnerabilities that are difficult to remedy in a monolith because interventions in the entire code are necessary. Modern microservices can be updated more quickly and isolate potential weaknesses.

• Need for rapid scaling: Especially in e-commerce or in strongly growing companies, we see peak loads that the monolith handles poorly. A finely granulated system landscape clearly shows its strengths here too.

• Skills shortage in old technologies: Anyone struggling to find developers for outdated programming languages must find ways to implement modernization quickly [4]. Microservices allow us to introduce new technologies and gradually minimize dependence on outdated systems.

In parallel, we recommend assessing the state of the existing application: are the code bases well documented? Which modules are indispensable, and which can be effectively separated? We have seen in projects that a detailed analysis of the monolith before starting the rebuild makes cost estimates and schedules more reliable. AWS also recommends evaluating criteria such as scalability problems or lack of reliability to determine the appropriate moment for decomposition [5].

Important Steps on the Path to Conversion

The path from monolith to microservices is not simply a technical migration project but rather a strategic and organizational change. Based on common methods, as also described in the 2024 Komodor article [6], we want to outline here the central phases:

1. Analyze the starting situation First, we get a clear overview of the existing monolith architecture, including data flows, modules, dependencies, and pain points. A feasibility study — both technical and economic — should also be part of this phase.

2. Define goals and set priorities Do we want to achieve rapid scaling, greater fail-safety, or primarily simplified maintenance? The more concrete our goals, the better we can later measure project success.

3. Choose a migration strategy In practice, several strategies exist:

   • "Strangler Fig Pattern": We gradually encapsulate individual areas out of the monolith and implement them as standalone services [7].
   • "Incremental refactoring": We break down individual function blocks step by step and successively approach a complete microservices architecture.
   • "Big Bang": Here, in a single major step, we switch from the monolithic application to a completely new system [2].

   Which procedure we prefer strongly depends on risk appetite and on budget, personnel resources, and schedules.

4. Lay the infrastructure foundations Microservices require a suitable infrastructure that supports containerization and orchestration (e.g., via Kubernetes) or serverless services. This enables automated deployments and uncomplicated scaling.

5. Clarify data management Often, legacy databases are tightly intertwined with the monolith. For microservices, each service ideally needs its own databases or at least separate schemas. A coordinated data migration in legacy systems is therefore essential.

6. Implementation and testing In this phase, we begin with the practical implementation, which presupposes regular tests, continuous integration, and close monitoring. Microservices are more distributed, so we should establish reliable mechanisms for logging, tracing, and metrics.

7. Rollout and continuous improvement Once the first services are live, we evaluate performance, maintenance effort, and costs. Adjustments may arise regarding data architecture or monitoring approaches. We recommend further developing in small iterations to achieve gradual improvements.

Common Challenges and How We Tackle Them

Just as important as the advantages are the potential hurdles in the transition. Introducing microservices means not only establishing a new technology stack but also breaking up traditional structures:

• Complex service communication: Anyone running a monolith is used to all function calls happening internally. With microservices, services communicate via APIs or messaging systems, which must be integrated. Latencies must be kept in view and sensible orchestration established.

• Data consistency: Distribution across multiple databases makes transactions more difficult and can lead to inconsistencies when services work asynchronously. Thoughtful data models, event sourcing, and a suitable transaction strategy are necessary here.

• Increased DevOps effort: Instead of one build process for the monolith, multiple repositories exist. This requires more automation and mature deployment pipelines so that teams can work together smoothly. Atlassian reports in its migration example that deployment frequency increased significantly after a successful conversion, but only through investments in infrastructure and tooling [8].

• Cultural upheavals: A microservices architecture requires autonomous, cross-functional teams. The old model with a single large central development branch dissolves. Teams need freedom and clear responsibilities. Cerbos points in this context to Amazon's "two-pizza team" approach, in which small teams of 6 to 8 members each carry end-to-end responsibility [9].

• Legacy software as an obstacle: Anyone simultaneously trying to phase out or replace legacy systems often faces considerable legacy function dependencies. A carefully coordinated plan for modernizing legacy systems is needed here. The topic of reducing technical debt also gains urgency to implement clean services.

Our recommendation is to involve the right experts early, prepare for cultural change, and start with pilot projects. We can thus identify the greatest risks early and cushion them.

Best Practices and Success Factors

Every company has individual requirements for its IT landscape, but some success factors are independent of industry:

1. Use an API gateway: Microservices should be reachable via a central gateway that takes over authentication, monitoring, and load balancing. According to Komodor, an API gateway not only ensures a unified access layer but also enables central documentation and security settings [6].

2. Consider event-driven architecture: Through asynchronous communication via events, services can be coupled more loosely. In case of error, a service can react with a delay without blocking the system. Scaling mechanisms can also be set up more easily.

3. Establish a DevOps culture: Microservices teams need continuous integration, automated tests, and container orchestration. We thus accelerate deployments and reduce the risk of technical stumbling blocks.

4. Prioritize metrics and monitoring: Precisely because microservices are more distributed, central monitoring moves to the foreground. We should clearly define what data we capture: latencies of individual services, resource consumption, error rates, and other metrics. Only this way do we keep an overview despite a growing system landscape.

5. Step-by-step migration instead of Big Bang: In many cases, an iterative approach proves its worth. We first decouple clearly delimited components (e.g., user management) and bring them into production as standalone services. We thus quickly gain practical insights without endangering the entire system.

6. Adapt organizational structures: Anyone who wants microservices must break down silos. Cross-functional teams that take holistic responsibility for a product or service usually show the highest effectiveness. According to Cerbos, this succeeds when leaders set clear goals but delegate operational decisions to the team [9].

7. Early involvement of employees: To minimize uncertainty and resistance, we recommend training, workshops, and regular updates so that all employees become familiar with the new architecture. Anyone who understands the advantages and sees how maintenance and collaboration improve is more likely to embrace the change.

Comparison: Monolith vs. Microservices

For a better overview, the following brief comparison may help:

| Aspect | Monolith | Microservices | |--------------------|-----------------------------------------------------------|------------------------------------------------------------------------------------------------| | Scaling | Entire application is scaled up, resource-intensive | Each service scaled separately, more efficient resource use | | Fail-safety | One error can affect the entire system | Isolated services, an outage rarely propagates system-wide | | Deployment | Large, time-consuming releases, high risk | Fast, independent deployments with lower overall risk | | Maintenance | Tight dependencies, difficult to update | Clear separation, services can be maintained or modernized individually | | Technology choice | Usually only one tech stack per application | Different programming languages/frameworks possible, ideal for heterogeneous requirements |

Especially with regard to flexibility and future viability, we see clear advantages on the side of microservices. At the same time, no one should underestimate the complexity that comes with orchestrating larger service landscapes.

Practical Examples

• Netflix: Already in 2009, Netflix began the step away from the monolith toward a cloud-based microservices architecture to ensure operations with rapidly growing demand [8]. Today, Netflix uses over a thousand microservices and can update new functions hundreds of times per day in the live system.
• Atlassian: Jira and Confluence were converted from a stateful, single-tenant monolith structure to a multi-tenant cloud-native architecture. Atlassian was thus able to significantly increase deployment frequency [8].

We also observe comparable scenarios in the German mid-market. Especially manufacturers or trading companies with grown ERP landscapes that have been developed monolithically for decades are increasingly relying on microservices. Automatic data exchange with partners, automated adjustment of production capacities, or accelerated launching of new digital products are just some examples that become realizable through a decoupled system architecture.

The ROI of a Successful Conversion

As varied as the business goals are, the positive effect on costs, time-to-market, and quality level is in most cases unambiguous. We regularly see that companies after the conversion:

• Reduce maintenance costs of legacy systems, because fewer dependencies exist within the code and targeted updates can be carried out.
• Increase development and deployment pace, since new features can be integrated faster without causing long downtimes.
• React better to security gaps, because affected services can be updated in isolation.
• Carry fewer outage risks, because errors in one service do not have to bring the entire system to a halt.

A cost-benefit forecast is often difficult to produce at the beginning; nevertheless, we recommend defining specific metrics to measure the effectiveness of the microservices migration. Possible KPIs include the mean time between deployments, the mean time to recovery from errors, or working time saved through automated processes.

In the long term, companies benefit from improved innovation capability: once the foundation is in place, we can launch new services agilely instead of first having to fight through a massive, monolithic code base. This makes it easier to react to market changes and quickly test new business models.

Sustainable Implementation and Outlook

The switch from monolith to microservices is not a short-lived experiment but a permanent modernization strategy. If the conversion succeeds, we have created a foundation for continuous development and the introduction of additional services. But this is exactly where the importance of sustainable governance lies:

• Clear responsibilities must be defined within the teams so that each service has an unambiguous "owner."
• Documentation and monitoring must be continuously updated, since the system landscape changes dynamically.
• New technologies such as containers and orchestrations (Kubernetes) or serverless architectures should be regularly evaluated to secure competitive advantages. AWS explains cloud-native decomposition patterns that support the step toward highly scalable services [5].

A microservices architecture is a win for companies that want to assert themselves in times of skills shortages, growing competitive pressure, and rapidly changing market demands. What is decisive is that we don't just build new software but also adapt the organizational culture. Cross-functional teams, iterative processes, and a data-driven mindset make the difference between a purely technical redesign and an actual modernization.

Conclusion

The leap from monolith to microservices requires thorough planning, an appropriate technical foundation, and organizational change. For many companies in the German mid-market, however, this step is more than just a fashionable IT project. It offers the opportunity to resolve long-standing bottlenecks in the maintenance and further development of individual legacy software and at the same time to position oneself in a future-proof way.

We have experienced in many projects how even the first successfully migrated services strengthen confidence in new technologies and measurably increase efficiency. In the long term, not only maintainability improves, but we also gain higher innovation speed and more flexibility to react to market changes. Of course, the construction of a service-oriented architecture remains complex, since topics such as reducing technical debt or shortage of skilled workers for old technologies do not disappear overnight. But anyone who consistently takes the first steps, sets clear goals, and prepares their team for cultural change will quickly feel the added value.

Ultimately, what matters is that we focus on the long-term perspective. Microservices are not a trend topic but have long been an established foundation of modern IT landscapes that combine agility, robustness, and variety in technology choice. Anyone coming from a monolith and daring the leap not only lays the basis for current modernization projects but also creates a sustainable framework for confidently mastering future challenges. By implementing our modernization strategies for legacy software and recognizing the value of more agile, decoupled applications, we can actively shape the digital transformation — instead of running after it.