Developers often talk about splitting their projects into microservices without a clear reason. This intention doesn’t always stem from specific requirements or a well-defined purpose. Instead, it’s often driven by trends: "all the big companies are doing it," "it’s faster," or "it’s modern."
But this way of thinking is problematic. Architectural decisions should be based on clear reasoning, not fads. In this article, I’ll share some of my thoughts and steps to help you decide whether you really need microservices.
Step 1: Understand what you have and why
I once read a great thought: architecture is about compromises. Before moving your architecture to something new, you need to understand why your current architecture exists in its current form.
If you’re working with a legacy system, your team probably has jokes about it. Like thinking that many things were written poorly or without purpose. Maybe that’s true, or maybe it’s not. Either way, you need to figure it out. Legacy systems often reflect the constraints, priorities, and decisions of the past. Of course, they can also contain a lot of spaghetti code or logic gaps due to the age of the project.
When you change your architecture, you will lose some benefits and gain others. For example, a monolith might be easier to debug and deploy, while microservices offer scalability and modularity. Understanding the trade-offs of your current system is the first step toward making an informed decision.
Step 2: What do you want to solve?
Every action needs a reason. If you’re just curious and want to try something new, that’s fine for personal projects, but not for business-critical systems. Experimenting with a new library in your work project is one thing, but moving your entire project to a new architecture is another. The latter can have significant consequences.
It’s important to identify the specific problem you want to solve. This will guide how you split your monolith into microservices. Different problems require different approaches to decomposition. For example:
- Scalability issues: Split services based on resource-intensive components.
- Team bottlenecks: Divide services based on team ownership and autonomy.
Knowing the problem you’re solving will also help you prioritize which parts of your system to move to microservices first.
Step 3: What resources do you have?
Before making any significant architectural changes, evaluate the resources available to you. Transitioning from a monolith to microservices is not just a technical decision, it’s also an organizational one. It requires time, skilled developers, and infrastructure.
Ask yourself:
-
Does your team have the necessary expertise?
Microservices introduce complexities like distributed systems, network latency, data consistency, and observability. If your team isn’t experienced in these areas, you might create more problems than you solve. If microservices are necessary but your team lacks expertise, consider taking small steps while studying the new concepts. -
Do you have the time and budget?
Splitting a monolith into microservices is not a weekend project. It requires careful planning, implementation, and testing. Maintaining microservices can also be more expensive due to the need for robust DevOps practices, monitoring tools, and potentially higher cloud costs. If your team is small and you don’t need microservices for ownership distribution, you might need to hire more people to maintain the new architecture without slowing down feature development. -
Is your infrastructure ready?
Microservices thrive in environments with modern CI/CD pipelines, containerization (e.g., Docker), orchestration tools (e.g., Kubernetes), and scalable cloud platforms. If your current infrastructure isn’t ready, you’ll need to invest in upgrading it first. This investment, however, can provide additional benefits even if you don’t adopt microservices immediately.
Step 4: Evaluate the trade-offs
As mentioned earlier, architecture is about compromises. Microservices come with their own set of trade-offs, and it’s essential to weigh them against the benefits. Here are some key considerations:
-
Complexity vs. Modularity
Microservices allow you to decouple parts of your system, making it easier to develop, deploy, and scale individual components. However, this comes at the cost of increased complexity in communication, data management, and debugging. -
Performance vs. Scalability
A monolith often has better performance because everything runs in the same process. Microservices, on the other hand, introduce network overhead and potential bottlenecks. The trade-off is that microservices can scale independently, which is beneficial for handling specific bottlenecks.
Note: When I talk about monoliths, I don’t mean a single service that does everything. Your monolith might already interact with other services, such as sending data to a machine learning service for processing.
- Team Autonomy vs. Coordination
Microservices enable teams to work independently on different services, which can speed up development. However, this requires strong coordination to ensure services integrate well and follow consistent standards. Without this, you risk creating slow coordination and unproductive communication. The more people work on a project, the higher the communication costs. To prevent these costs from becoming too expensive, your team needs good management and organizational skills. Without them, this is unlikely to happen on its own.
Step 5: Start small and iterate
If you decide that microservices are the right choice, don’t try to split your entire monolith at once. Start with a small, well-defined part of your system that has clear boundaries and is relatively independent. This could be a feature or module that is easy to extract and has minimal dependencies.
For example, if you have a monolithic e-commerce platform, you might start by extracting the payment processing or user authentication module into a microservice. This allows you to:
- Test the waters with microservices without overwhelming your team.
- Learn from the process and refine your approach for future migrations.
- Minimize the risk of disrupting your entire system.
Remember, microservices are not a silver bullet. They are a tool, and like any tool, they should be used only when they solve a specific problem better than the alternatives.
Conclusion
Before jumping on the microservices bandwagon, take a step back and evaluate your situation. Understand your current architecture, identify the problems you want to solve, assess your resources, and weigh the trade-offs. If you decide to proceed, start small and iterate.
Microservices can bring significant benefits, but only when implemented thoughtfully and for the right reasons. Otherwise, you might find yourself with a more complex and less maintainable system than the one you started with.
On the other hand, you can have a service-oriented architecture with a monolith as one of the services. This can happen for various reasons. For example, you might have very tight requirements and audits for your payment system, or your ML team might maintain another service to process images or other types of data.
In the end, architecture is about solving problems — not following trends. By focusing on your system’s unique needs and constraints, you can make decisions that truly benefit your project and your team.