Microservices or Monolith: which architecture to choose for building your application

It seems that all the successful companies are adopting microservices. Amazon, Netflix, eBay, PayPal, and other well-known brands have already migrated from monoliths to microservices. Meanwhile, many businesses consider that following their example will lead to spectacular results.

So should your business follow this trend and shift to microservices? Or maybe the good old monolithic architecture is the best way to go?

In this article, we are going to figure it out.

How does the Monolith work?

A monolithic approach is a traditional way of developing an application. All the services within the monolithic application are combined in a single large unit. So it is built and deployed as a whole with one big code base. All the components of such an application are tightly coupled and managed in one place.

The standard monolithic application includes a user interface, business logic, and a data access layer that communicates with the database. The unified nature of a monolith means that all the functions are served and managed in one place. Any changes in the application affect the whole stack.

How do Microservices work?

In the microservices architecture, the entire application is broken down into smaller independent components. Each component (microservice) is responsible for a specific function.  All the services are independently developed, deployed and maintained. Splitting up a complex application into a collection of separate services makes them easier to understand and faster to develop.

Microservices do not have a centralised infrastructure and communicate with each other through defined methods called APIs (Application Programming Interfaces). Each service has its own logic and a database.

Aspects to consider when choosing an architecture for your application

Introducing changes

In a monolithic architecture, the components are tightly coupled, so every code change influences the entire application. When an application grows in size over time, the codebase becomes larger. So it is more difficult to make new changes, and rapid changes are almost impossible. On the contrary, it is much easier to add new features to a microservice application. In a microservices architecture, any change affects only one particular service. Therefore, you can adopt changes faster, and the harm from any fault is much lower.

Cross-cutting concerns

Cross-cutting concerns are the parts of the program that affect the whole application. They include logging, security, caching, handling, performance monitoring, and other concerns.

They relate to the system as a whole and require system level approach. As a monolithic application is a single and unified service, there are no problems with the implementation of such services. However, in a microservices architecture, they have to be applied to every microservice, which makes the overall development process more complicated.

Winner: Monolith

Testing

The distributed nature of microservices makes their global testing more complex and difficult. It is easier to test separate parts of a microservices application but not the whole one. On the other hand, an average monolithic application is much easier to debug and test. Since a monolithic app is one indivisible unit, you can run end-to-end testing much faster.

Winner: Monolith

Scalability

Scaling a monolithic application is usually much harder than a microservice one. In a monolith, you should always scale an entire application and deploy the whole codebase instead of scaling only the services needed. On the contrary, microservices are more independent so they can be scaled and deployed separately.

Winner: Microservices

Adopting new technologies

In case of a monolith, if you want to apply a new technology, you have to rewrite the whole application. Of course, it is time- and cost-consuming and there is no guarantee that it will pay off in the long run. When it comes to microservices, the engineering teams have more flexibility and do not have to stick to the technology chosen from the start. They can apply different technologies and frameworks to each microservice.

Winner: Microservices

Managing the process 

In contrast to the monolithic architecture, a microservice application is a distributed system, so you have to tackle all the organisational challenges associated with its complexity. It means you need to establish effective communication between its parts as well as manage all the services within one application effectively.

Winner: Monolith

So which architecture to choose?

Monolith

If you have a small team developing a simple application, you should start with a monolith. Building a monolithic application requires lower upfront investment and enables increasing the speed to market. So if you want to launch your lightweight application quickly or validate your business idea, then monolith must be the right option for you.

Also, building a microservice application requires proper expertise and technical skills. If your engineering team lacks experience in microservices, you will end up spending much more time and money on building such a solution. So make sure your architect has the necessary expertise.

Microservices

A microservice architecture is an excellent solution for a complex application with a large code base. It is ideal for platforms with many services, user journeys and workflows. Microservices will provide you with the high level of agility and the opportunities to develop, deploy and scale all your services separately.

Also, it is especially good for the projects with several engineering teams located in different geographical zones. In this case, each team has ownership of the service and can implement changes much faster with less risk. But without the microservices expertise, adopting this technology is unreasonable. So make sure that your team is prepared to tackle all the challenges associated with building a microservice application. If not, you can always hire a software development vendor experienced in developing microservice applications and maintaining them efficiently.

Afterword

A microservice architecture is not a silver bullet. Yes, it can bring solid advantages such as increased scalability, flexibility, agility, and many others. In some cases, when there are large code bases and multiple engineering teams, adopting microservices is a perfect solution. Whereas, a monolithic architecture still has its strong and durable advantages in many business cases.

So, first and foremost, you should choose the architecture that would satisfy your business and software development needs.

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