Monolith vs Microservices Architecture: Which One Is Better for Your Business?

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The battle microservices vs monolith continues for a while now because software developers and business owners still try to determine which architectural style is the best to select for their applications. The product scalability, efficiency, and competitiveness depend on which one they choose – monolith approach and microservices.

While monolith architecture has been around for a long time, microservices came to light a few years ago and are accelerating nowadays. In comparison with the monolithic approach, which is a default model for building software applications, microservices allow for tangible opportunities for businesses to enhance scalability, flexibility, and agility. Read on to jump into more specific details, pros, and cons of each architectural style and figure out why/why not you should switch to microservices. Will your choice be successful for your business?

What is monolithic architecture?

If the application is developed using the monolithic approach, it is created as a single and autonomous unit consisting of a database (consists of many tables in a relational database management system), client-side user interface (contains HTML pages, UI, and Javascript to run in a browser), server-side application (performs domain-specific logic, retrieve and update data from the database, and handles HTTP requests).

All these parts are interconnected and function in one location. This means that when stakeholders want to update the application or make changes, they need to handle the same set of code and deploy the updated version of the server-side interface which can affect the user-side performance. Monolithic-based applications do not need an API to communicate.

The majority of legacy applications use monolithic architecture. In our article about how to perform a legacy system modernization, we went over modernization approaches and how to choose the rights one to achieve better results for your business.

Microservices approach explained

With business-oriented APIs, the microservices approach allows for the splitting of the application into a collection of smaller independent and self-sufficient units/services which makes backend operation unnoticeable. They can be reused in multiple business processes or over different digital touchpoints due to their own business logic and database. Thanks to each microservice that has its own database, this approach ensures the principle of loose coupling. Moreover, each type of database can be used exactly for the specific needs of each microservice.

The migration of the application from a monolithic architecture to microservices helps reduce technical debt. There are a lot of differences, pros, and also cons of each architectural style. Let’s take a look at the main differences of monolith vs microservices and dive into their benefits and advantages so that you can estimate which solution will best suit your project.

What are the differences between monolithic and microservices-based architectures?

So let’s sum up the differences between the two architectures and outline the aspects where their software development processes differ.

• Consisting of three parts (UI, database, server-side application), monolith architecture exists in a single codebase. The architectural style of microservices is aimed at creating the application out of small independent services with an independent database.
• Within monolithic architecture, it is hard to support and implement new shifts since the whole system requires redeployment. In microservices, each element can be scaled independently without downtime.
• If a bug or issue occurs, in the monolithic-based project, the whole system can be ruined. The microservice environment is resilient allowing to prevent the failure of one service to another.
• Using the monolith approach, dev teams cannot use new tech, languages, and frameworks since monolithic architecture is not flexible. As opposed, microservices are easily integrated with new technologies to solve business goals.
• Within a monolithic environment, it is impossible to distribute the dev team’s efforts due to the massive indivisible database. With the microservices approach, developers can work independently on different elements of the solution.

Monolith: benefits and drawbacks

Although it might seem that a monolithic architecture does not have any benefits, there are some. And depending of the technical case, one or the other approach to building the architecture of your software product can be used.

Advantages of monolithic applications:

• Easy development and deployment. There is no need to worry about the orchestration of elements and making updates in each entity (as in microservices architecture). Being a traditional way of building applications, the monolithic approach allows developers to easily develop and deploy apps thanks to the existence of numerous tools. You do not need to deal with many deployments – just one file or directory.
• Higher performance. Since monolith doesn’t require APIs for components to communicate, users experience less latency and faster response time in contrast to a microservice-based environment. Therefore, the monolithic approach is more streamlined owing to one centralized codebase that can serve the same purpose.
• It is easier to handle cross-cutting concerns. Logging, error detection, caching, memory management, – all this can affect the entire application. With monolith architecture, developers can easily implement workflows that require different elements of the application.
• Easy to debug and test. Debugging and testing processes are automated since there is no need to test different run-time environments separately as in microservices.

Disadvantages of monolithic applications:

• A complex system of code. As the application grows and needs upgrades, it is complicated to implement changes across the entire application. Therefore, scaling-up issues occur which results in a long-term overall process. Due to the low flexibility and tight coupling of monolithic-based applications, it is complicated to add new changes and to maintain independent scaling of services/components. Moreover, when a monolithic app scales up, it is hard to comprehend the complex system of code because of a single codebase that is impossible to split into separate components.
• Limitations in the adoption of new technologies. In order to accommodate new technologies and integrations into the particular functionality of the application, the whole architecture needs to be rewritten which means a huge challenge due to time and cost restraints.
• Impossible to distribute the team efforts. The business logic of the huge indivisible single-unit database is hard to understand for developers-newcomers in the project.

Microservices: benefits and drawbacks

The main benefit of microservices is loose coupling which means that each microservice has a single responsibility providing a single functionality. Thereby, each database attached to each
microservice is decentralized allowing the use of the database that fits certain microservice’s needs.

So, the main principles of microservices concern the following:

• Each microservice has a single responsibility: The number of required functionalities is equal to the number of microservices.
• Microservices solve business purposes. Thanks to the ability to integrate different technologies, microservices are suitable for solving the business goal based on business requirements.
• Microservices are designed for failure. That means that error in one component does not affect the functionality of others or the whole system.

Advantages of microservices architectures:

• Better resiliency. Thanks to the isolated nature of modular components developers can easily troubleshoot and mitigate the root of the problems within a microservices-based environment.
• Integration with a variety of technologies. Based on the particular business requirements, the development team can adopt any technology that will be the best fit. Therefore, developers are not limited by the technology selected at the beginning of the project. Each functionality can be applied with any language or framework.
• Streamlined development process. Before adding or modifying a functionality, the development team does not need to understand the business logic of the whole application since all the components are isolated. This optimizes the devs’ workload and reduces the communication between team members.
• Increased scalability. Each microservice is self-contained and isolated from the rest modules allowing developers to make necessary updates or upgrades by using different languages/frameworks without compromising compatibility. There is no need to scale up the whole system (as with monolith) which is time-consuming and non-cost-effective.
• Continuous delivery is made simple. To make small change iterations is much easier within a microservices environment than with a monolithic approach as developers do not need to modify the whole system. Microservices consequently allows building, testing, and deployment of applications just in minutes. Since changes need to be applied to certain microservice, other stable working services stay untouched which in turn makes the delivery process fast and much easier.
• Enhanced revenue. Fast iterations (we mentioned this above) and elimination of downtime have an impact on user experience and loyalty. Also, developers are motivated to maintain complex applications and complete projects in time. All this fosters the app development process ensuring an increase in revenue as well.

Disadvantages of microservices-based applications:

Considering a big advantage of scaling-up and the possibility to be integrated with different tech stacks, microservices still have their drawbacks inherent to complex natures.

• Cross-cutting concerns are difficult. It is a complicated task to move data from service to service in a consistent and sensible way. Therefore, logging, caching, service registration, for example, have to be maintained in each service.
• Complex testing. The more complex the structure of services is, the more complex will be the testing process, especially the testing of interactions between services.
• Less secure. With a multitude of modules and databases, inter-communication can be a reason for cybersecurity attacks.
• Debugging issues. In order to identify the root cause of the bug, dev teams have to verify each service functionality separately.
• Cost overheads. The need for additional services/units may lead to additional expenses.

Summarised comparison of monolith vs microservices

In the table below you can see a brief comparison that illustrates all the important differences between a monolithic and microservices approach in application architecture:

Why do enterprises adopt microservices?

Most businesses launch their products by designing their infrastructures as a single monolith. Every time when developers want to upgrade or scale existing systems, they have to carefully untangle dependencies which is time-consuming and, to change or add features in a monolith may lead to code disruption for the entire application.

Therefore, a good solution is to divide the functionality into small distributed independently-running microservices. Amazon, Netflix, Uber, Etsy are well-known examples that switched to microservices from monolithic-based applications. If you are thinking about adopting microservices on AWS, here’s a short guide to help you.

Which architecture will best suit your business?

There is no unambiguous answer to this question unless you define your business requirements and estimate your project budget, projections, and revenue.

Taking into consideration the fact that the monolithic approach encompasses easy development and fast deployment – it will be a good match for small businesses and startups. But if you are going to implement changes and upgrade your application, then microservices will help to achieve this goal. Let’s come up with the following scenarios.

Reasons to select a Monolithic Architecture:

• Plan to build a small app that does not need to be upgraded in the future. In this case, the complexity of the microservices architecture will be a drawback for your project.
• Need to deploy your product as soon as possible.
• Do not have a team of experts who can split the system into separate functionalities and divide responsibilities.

Reasons to select a Microservices Architecture:

• Plan to launch a complex and scalable application. If in the future, you are going to add new functionalities to your application and upgrade it, the adoption of new advanced tech stacks will be your best solution. For this purpose, the microservices approach will be your rescue, in particular, to gain a competitive advantage.
• If you have the experts tightly connected with microservices who have solid experience in this field

Our team of engineers accomplished a new website for one of Europe’s largest airlines with 3x improved performance and additional custom apps. The reason for legacy modernization and migration to AWS cloud was the fact that the main website was a front-end monolith that was not suitable for implementing user-centered changes that wouldn’t affect the whole system. We implemented microservices front-end architecture allowing us to deploy different parts of the application separately with no need to redeploy the entire system.

Conclusion

Nowadays Agile approaches among developers’ teams make microservices more preferable over monolithic-based applications. However, that does not mean that one is better than the other. You have to understand your business purposes and estimate your project as a whole. If you are a startup for instance, and adding new features and upgrading your application is not what you are looking for, then monolith will probably be a good option for you. You will find microservices a much more progressive approach than monolith for your project if your goal is to grow and scale up your business in the long run. In this case, you might want to hire the best experts who can evaluate your project and offer you the best solution.

Author Andriy Stelmakh Software Engineer at Euristiq

About

Andriy is a certified AWS Solutions Architect and a skilled software engineer with more than 10 years of experience. He is passionate about working on Cloud-based projects, helping to deliver data-driven business value across industries.

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