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Why you should move from monolith to microservices

(Image credit: Image source: Shutterstock/Kalakruthi)

In this article we’ll talk about microservices and how to shift to it from a monolith architecture. We’ll find out how to adapt to such changes with minimum risks for your organization. In fact, we’ll figure out how to accomplish this with benefits. Excited? Let’s jump right into it.

First off, let’s discuss why you need to make such a transit. At a certain point, you may find yourself in a situation where adding new important features to an existing codebase becomes really difficult and time-consuming. Moreover, it turns out that the cost of a new functionality outweighs the benefits it may bring. The solution to this challenge might be microservices.

What are microservices? 

There is no clear definition for it. So let’s stick to Jonathan Johnson and Laura Shiff’s description: Microservices are a specific method of designing software systems to structure a single app as a collection of loosely coupled services.

Instead of a monolithic approach, each microservice component has:

  • Own CPU 
  • Own runtime environment 
  • Dedicated team working on it 

This architecture means each service can run its own unique process and communicate autonomously without having to rely on the other microservices or the application as a whole.

It has become a trend for many organizations. Such corporate giants as Amazon, Uber, and Netflix already implemented this architecture. The idea behind it is simple: extracting massive components into multiple, deployable, and self-sufficient functional entities grouped by a certain purpose. Every element is responsible for its own specific functions and interacts with other components through an API.


This adoption may bring your company many benefits including improvements in resilience, high scalability, faster time to market, smooth maintenance, and so on.

However, the migration process may turn out to be quite challenging, especially for organizations that operate large and complex systems with a monolithic architecture. But the good thing here is that microservices can peacefully coexist with any monolithic program.

You can stretch this migration process in time thus reducing immediate cost and effort loading, and stay fully operational through the whole process. Moreover, you don’t necessarily need to move the whole solution to microservices. You can go with a hybrid strategy, extracting only those parts that become hard to handle inside the monolith and keep the rest of the functionality unchanged.

Why convert? 

The typical monolithic architecture includes such problems as a slow delivery process, system scalability, defects detection, verification difficulties, and so on and so forth. Software parts are tightly combined inside this architecture, thus even the slightest changes affect the whole app or program and require redeployment. This ends with a very time-consuming and painstaking operation. The same goes for scalability. You need to scale the entire application.

Well-designed and implemented microservices help address these issues by splitting up the large app into the tiniest components which are divided by specific domains and communicate with each other via APIs. But to the end-users, it looks like a single application.

Each of these services can be created, tested, and changed separately. If something fails — your development team will be able to quickly fix this without affecting the work of the whole app.

To sum, the benefits are following:

  • easier deployment and maintenance 
  • reduced downtime through fault isolation 
  • flexibility in choosing tech stack and easier scalability 
  • simplified coordination within the teams 

However, once you introduce such architecture, integration becomes a challenge. This requires special attention to both the design, implementation, and testing part of the transition process. 

Switch smartly 

The transition from monolith requires careful and thoughtful planning. The best thing is to start with cutting off parts of the functionality from the monolith one after another, step-by-step. Use an iterative approach and keep those parts small. This will reduce migration risks, and you’ll have better control over the whole progress.

Extract everything that can be isolated first. Only after that deal with the remaining functionality. It can either be rewritten into separate microservices from scratch or left within the monolith. Either way, it will be far easier to maintain after most of the functionalities have already been detached.

With this approach, a typical process would include the next steps:


- Identify microservice candidates and create a backlog

First and foremost, you need to create a backlog for microservices adoption. In order to do this, you need to identify candidates — parts that should be turned into separate microservices. Then you need to prioritize those to form a queue for further transition. 

Of course, the best option would be if those candidates are functional groups that can be isolated from the monolith with minimum effort. Also would be good if they can solve some issues that your application already has.

The most obvious candidate would be an area that has certain resource and performance utilization issues. Or it could be a domain area that will unblock other microservices' separations.

If you are looking for a more inclusive approach to determining what can be detached from the monolith, the best strategies that you can apply during your switch to microservices would be:

  •  Dividing the App into Layers 
  •  Splitting the App into the Domain Areas 
  •  Dividing the App into the Modules

Iterative implementation (this set of steps is repeated for each microservice)

  • Choose the refactoring strategy 
  • Design the microservice and change according to CI/CD and testing process 
  • Set up CI/CD 
  • Implement microservice 

Make sure you have available professionals who will take care of your entire migration process.


Moving to microservices is surely not an easy task, although it can be simplified if done sequentially. They have their advantages, but there must be really good reasons for such a switch. It requires great efforts and highly skilled specialists, who can plan and execute the migration.

You can think of such migration if your existing architecture has become too complex to operate and manage and put your best efforts into strategy and design. Today scalability and agility are keys to success — microservices provide both of these. With the proper planning, design, and proper implementation, investments into migration will pay off quite quickly.

Sigma Software

Sigma Software Group, ranked in the World's Top 100 Outsourcing firms by IAOP, is the Swedish-Ukrainian company that provides top-quality software development solutions and IT-consulting to 170+ customers all over the globe.