Monolithic vs Microservices Architecture

By: Albert McQuiston | Updated: 2024-12-09 | Comments | Related: > Application Development

Problem

Before starting any major software or app development project, many project managers are confused about monolithic and microservices architecture. The following article will clear up any confusion on the topic.

Solution

Change is inevitable. Who knows this better than us? We humans keep changing or evolving thanks to ever-increasing technological advancements. At one point, if technology becomes the Wild West, there is another one standing around the corner waiting to be explored and experienced. The IT industry has experienced a fair number of changes over time. At this point, most tech-savvy people are well-versed in the concept of microservices; it's booming a lot lately. But can you recall what was before that? Monolithic architecture. The following article focuses on what microservices architecture and the monolithic approach are, how both concepts are beneficial, where exactly the difference lies, and above all, which one is better: Monolithic or Microservices Architecture.

With the evolution of new technologies and digital transformation, adopting new technologies is way more important than ever. It doesn't matter whether you are a startup, a mid-size business, or a large enterprise, accepting and adapting technology is a must not just to remain competitive and stay relevant. Choosing the right architectural style is pretty important. Also, it depends on your unique needs and requirements. Both monolithic and microservices are predominant architectural, so which one should you choose? Well, you need to have a proper understanding of the two. Let's begin!

Monolithic Architecture

The monolithic architecture features business logic, a user interface, and a distinct range of components within the same codebase. This architecture is known for using a single programming language, a single repository, and a single environment, which means any changes made can have a huge impact on the entire app.

This approach was well-known until the microservices architecture came into existence. It was known due to several factors, such as tight coupling, which means components are pretty much dependent and interconnected.

No wonder monolithic architectures have remained a solid choice as the standard architectural style for years, especially for startups and small-scale organizations. In fact, the approach continues to be considered when developing apps that do not require many updates over time.

Microservices Architecture

Microservices architecture is when all components of the app are bifurcated into independent, loosely coupled modules. The entire app is broken down into small and independent services that successfully communicate using APIs. Each module and service is comprised of its repository, logic, and features - an amazing deployment process. Unlike the monolithic approach, microservice architecture is cross-functional where every layer of the stack can be organized according to different business units. In this modern and practical approach, each service can be successfully developed by different team members and still the interoperability can be stabilized. For example, if you are developing a navigation app, separate services for differing modes of transport, such as car, bus, subway, or walking, must be incorporated. Here the information given is also in accordance and relevant. For example, if you require the current traffic conditions for cars in a specific city, looking at the subway conditions will not be useful.

"According to a 2020 survey by O'Reilly, 28% of respondents' organizations had been using microservices for three years or more." One of the obvious benefits of considering microservices architecture is speed, flexibility, and scalability. Also, these apps no longer require going through centralized points since they can communicate seamlessly via APIs. With time, meeting user needs and offering valuable experiences is important, just like keeping up well with ongoing and instant shifts in the market.

The API-first approach is the core crux that ensures seamless performance and scalability, in addition to easy third-party app integration, scaling up the app, seamless testing of your app, etc. Some of the key principles of microservices include:

Building Around Business Capabilities - The need for adopting a proper tech stack is much less since the tech can adapt automatically on a per-case basis.
Single Responsibility - A solid design pattern simplifies any microservice, so only one core functionality is needed.
Design with Failure - In case one microservice fails, does this mean the entire system fails? Of course not! Other functionalities remain intact even if one module fails.

Detailed Comparison Between Monolithic and Microservices Architectures

Now you understand both concepts. It's time to spot the actual differences.

Comparing Pros and Cons

Let's first see the advantages and disadvantages of both architectures.

Pros of Monolithic Architecture

Less Cross-cutting Concerns - Cross-cutting concerns are when the concerns affect the entire application, like logging, handling, caching, performance monitoring, and so on.
Seamless Debugging and Testing - In comparison to microservices, this approach is amazing when it comes to debugging and testing. No wonder single-tiered apps are easy to debug and test. Also, end-to-end testing is conducted in a faster manner.
Easy Development and Deployment – Last, but certainly not least, the monolithic approach is easy to develop as well as deploy. This is the sole reason why it was once considered the standard for building apps across the globe.

Cons of Monolithic Architecture

Code Complexity - Imagine you are developing a building. There won't be any issues to a certain height. But after a while, the level of instability might increase, leading to severe shaking or maybe collapse. Monolithic architecture is no different. Once it scales up and up, things might become too complicated to deal with since it is difficult to maintain a large codebase.
Highly Interdependent Components - Another issue with monolithic architecture is that implementing relevant changes within a large and complicated application with high coupling can cause major issues. As time goes by, the tech challenges automatically increase.
Limited Scalability and Other Tech-related Barriers - Limited scalability is a disadvantage here. In addition, applying cutting-edge technology can also be an issue. In the worst scenario, the software might have to be rewritten.
Centralized Data Store - Monolithic architecture has a centralized database from which everything is managed and stored. Once the application starts scaling, the database becomes gradually harder to manage and its speed becomes less efficient.

Pros of Microservices Architecture

Independent Services - One of the obvious benefits of microservices is its independent architecture. Each service is developed independently of others and one service won't affect another. Moreover, different resources aren't dependent on irrelevant functionalities. Microservices can store customer information if required. Microservices can interact with customer service to retrieve required customer data if not stored locally. Database joining can be done using two methods. One method is backend joining where a backend service makes multiple calls to different microservices to collect the aggregated data using APIs and sends it to the client after processing it. Another method is called front-end joining where the front-end application makes an API call to each microservices and then combines.
Ability to Use Multiple Tech Stacks- Each service is developed on an independent basis. One can successfully choose the tech stack and programming language, which works wonders for each and every function. In other words, you can choose the kind of tools required for each service; there is no concept of a "one-size-fits-all" approach.
Reliability - As mentioned earlier, a monolithic approach can be hard to scale; fortunately, that's not the case with hybrid cloud microservices. Each function is loosely coupled and easy to optimize, test, debug, and fix independently.
Database Per Service- Each microservice has its own database, making the overall architecture easier to manage since other services cannot interfere. Also, if one database fails, it will not impact other services. In other words, you no longer need to put the entire app in downtime; instead, scale each service or tweak it wherever needed.

No wonder, microservice architecture is more scalable and reliable. What about the downsides? Are there any? Of course, there are.

Cons of Microservices Architecture

Time and Resource Consuming - If you see microservices on an individual basis, then each can speed up development, but slow down depending on the complexity of the app. Also, it can take a substantial amount of time. Due to dedicated databases for each service, data consistency becomes challenging.
Complicated Deployment - Since services are kept on a separate basis, it is very important to integrate them well into a full-fledged functional app. This should be done before they are deployed. With the rise in complexity, the deployment also becomes difficult.
Complex Testing - Independent services are also supposed to be tested individually in the end. But they require testing as a whole to see how everything works together.

Performance

The first and foremost differentiating factor is overall performance. Microservice architecture features a distributed nature, resulting in high scalability and improved app performance. Microservices assist in scaling up specific parts of the app which means you have comprehensive control regarding how the app performs. Fortunately, there are different types of tools, such as Kubernetes, that not only offer information regarding how each component is performing but also it is possible to auto scale for the best possible results.

Compared to the microservices approach, scaling up turns out to be slightly difficult because the monolithic architecture is tightly coupled. Here, the entire app must be scaled, causing an expensive venture. This is because the whole monolithic application needs to be scaled because of a single codebase if you want to scale certain functions in the application. This will ultimately lead to unwanted costly infrastructure upgrades. With the addition of more and more features, scaling the codebase becomes increasingly challenging. Nevertheless, for small and seasonal businesses with simple requirements that need rapid development, monolithic architecture can be advantageous.

When it comes to performance, the microservice architecture approach turns out to be way more enticing. But it doesn't mean you won't face roadblocks sooner or later. For example, the microservices architectural style mainly relies on APIs; however, they can be more vulnerable to third-party outages or performance issues due to poorly designed APIs. Monolithic applications also tend to use APIs with a single-entry point for the whole application. Monolithic APIs sometimes become complex and larger endpoints when they manage multiple responsibilities. Both architectures have their own distinctive ways of using APIs: one uses APIs to manage multiple functionalities, while the other uses them for specific responsibilities.

Operational Aspects

Another crucial factor to consider when spotting the difference between monolithic and microservices architecture is its operational aspects, such as development, testing, deployment, scalability, and fault tolerance.

Operational Aspect	Monolithic	Microservices
Develop	Extremely hard for developers and QAs to understand the code and business knowledge	Different kinds of cross-functional teams are considered to develop services to ensure quick turnaround times
Test	The entire app is tested	Each service is tested independently
Deploy	It can be successfully deployed as one single unit	Services can be successfully deployed on an individual basis ensuring easy rollout of new updates
Scale	Difficult to scale up	Easy to add new services, markets, and products
Fault Tolerance	If one part of the app fails, the entire system is doomed	It doesn't matter if one service fails; it won't affect or disturb the others
Database Design	Tightly coupled, single schema design	Each service uses a different schema
Maintenance	Easy to manage	Multiple services make it difficult to manage
Performance	Efficient for small applications	Individual service performance can be optimized independently
Security	Security glitches can affect the entire application	Services have their own security measures
Cost \ Licensing	Lower Initial Cost	Higher Initial Cost
High Availability	Difficult to achieve	Easier to replicate and achieve
Disaster Recovery	The entire app needs to recover	Services independently can be recovered
Upgrades	More complex	Upgrades can be implemented independently
Reporting and Analytics	Easy reporting due to a single codebase	Complex to get insights

When to Use

Now it's time to make the final decision, which one to choose and when.

Monolithic

The App Must Be Simple - Small solutions work absolute wonders here, especially the one that don't require any business logic, superior scalability, or flexibility.
It Needs to be Launched Quickly - If you want to launch the app in a quick manner, a monolithic approach is the best.
Lower Software Latency - Generally with these kinds of solutions, all types of communication are realized in a single stance of a deployed application. With less network communication, minimal time is taken for a data packet to travel successfully from one designated point to another.
Modular Approach - This architecture type is used for a code organization that is unified but still presupposes segmenting code into individual feature modules. If you want well-organized code, then there is no need to switch to microservices.
Business Applications - Traditional e-commerce website with all functionalities integrated into a single app, content management system (CMS) with functionalities like content updating, and authentication within a single codebase.

Microservices

Developing Complex Apps - The microservices architecture seems to have a reputation for developing complex and highly scalable apps. The best part is all this is done in an easy manner. If you want to plan a large app featuring numerous modules and user journeys, look no further than microservices.
Planning New Releases - Another crucial reason to consider it is if the app's ultimate requirement is to release new features and quickly time to market. Microservices allow for developing and deploying new functionalities separately in each service without the need to redesign the whole solution.
Fault Tolerance - Individual modules are isolated from one another. This means that if one system fails, other app parts will continue their work.
Use of Numerous Technologies - It is possible to choose relevant technology for different services that won't contradict.
Business Applications - Many modern applications use this architecture. For example, Uber uses microservices to manage services like profile management, ride services, driver allocation, and many other functionalities. Spotify music streaming app also utilizes microservices to manage user playlists, music streaming, recommendations, and many others.

Conclusion

Which one is better? Well, this is no longer a question because either of the two approaches you choose, whether it's microservices or monolithic, you will succeed if you pick the right one based on your requirements. Choose monolithic architecture if you have fewer complex requirements with a limited scope and development team. Otherwise, if you're looking to scale your application in the future and can invest more of your initial time and money, then microservice architecture is the right approach for you.

Next Steps

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About the author

Albert McQuiston is a software developer with more than 10 years of experience. He has worked with many companies and holds a bachelor's degree in Computer Science.

This author pledges the content of this article is based on professional experience and not AI generated.

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Article Last Updated: 2024-12-09