What Is the Difference Between Monolith Architecture and Microservice Architecture?

If you ask yourself this question, you probably have not yet decided which development architecture to choose for your application. Or maybe you have already built your product as a monolith and now consider migrating from monolith to microservices because you are amazed by the mind-blowing success of the microservices pioneers like Netflix and Amazon.

The main difference between monolithic and microservices architectures is how the application framework is organized. Monolith operates as a single monolithic block, keeping all its services tightly merged in one place and relying on one database. Its counterpart, microservices architecture divides an application into small, independent services (hence the term), each focusing on its separate function and communicating with each other through APIs. Microservices emerged to curb some of the monolith’s drawbacks such as code complication and scalability issues. However, newer does not mean better in this case.

Both monolithic and microservices architectures have pros and cons, and neither can be considered a silver bullet. However, both can work great at certain application development stages and business conditions. Which one to choose depends on various factors, such as what you already have, your design readiness, scalability requirements, etc. So in this post, we will look closer at their strong and weak points and give you some tips on choosing the proper architecture for your project.

Monolith vs microservices: pros and cons

Advantages of monolithic architecture:Advantages of microservices architecture:
1. Easy from scratch development. Since monolith keeps all its components in one place (and has fewer of them), it is easy to develop the whole application from the get-go, even for a small team on a budget.

2. Crystal clear architecture. Monolith is a simple and easy-to-comprehend structure with minimum components.

3. Simplified debugging and end-to-end testing. Since the whole application operates as a monolithic unit and the code is located in one place, it can be debugged and tested easily and quickly.

4. Secure data processing. Since the communication is inside the same unit, it is easier it keep it safe.

5. Easy onboarding. The code flow is easy to understand and to work with, even for new members.

6. Lower startup cost. With very straightforward development, monolith architecture is cheaper to build from scratch than microservices.

7. Optimized Performance. Monolithic applications can have faster in-process calls between different parts of the application. This can lead to more efficient execution and better overall application response times.
1. Faster, self-paced, flexible, and agile deployment. Every team works on its separate service at its own tempo without waiting for other dev teams, which shortens the deployment time.

2. No code tangles. Every microservice has its own codebase, which is always easy to track and debug, no matter how big the whole application becomes.

3. Tech latitude. The independent nature of microservices enables developers to go with the tools and languages that best fit their talents and work context. Changing the language/tool at any stage doesn’t impact the whole application.

4. Freedom of innovation and experimentation. The teams can test new approaches and change the code within their microservices without fear of crippling the whole application codebase.

5. Unlimited scalability. Every service within an application can be scaled up or down when it is the most needed (for example, to address a seasonal spike in demand) without harming the overall functionality.

6. Failure resistance. When one of the services goes down, the problem is locked inside until it is fixed without running into the risk of collapsing the whole application

7. Small teams. With a microservices architecture, you will need fewer people on board, as every service will require a minimalistic team to work on it.
Disadvantages of a monolith:Disadvantages of microservices:
1. Tangled codebase. As code builds up, it becomes harder and harder to track it.

2. Poor scalability. To introduce a change (even a very small one for only one function), you have to redeploy the whole system, which translates into scope creep and exceeding the budget.

3. Technology rigidness. Within a monolith, you won’t be able to adopt new languages or experiment with new tech and frameworks. Even migration from one version of a language to another is complicated.

4. Impaired resilience. If a bug appears, it affects the whole system. If one part of the app goes down, it collapses the entire app.

(It is worth mentioning that most of them emerge only when the application becomes too big.)
1. Knotty and expensive integration testing. Unlike service testing, which is trouble-free, end-to-end testing becomes a problem because of the boundaries between the services. Services need to be tested separately before testing how they work together, which leads to budget overruns.

2. Data security depends on the reliability of APIs. Communication between the services requires API gateways, which raises the security concern.

3. Resource dependency. Due to the fragmented nature of the application, deployment requires various resources (APIs), which makes the orchestration of deployment very complex.

4. Difficult to refactor/redesign. If you don’t have a polished design yet, the microservices architecture can be a bad choice because making the tiniest change in the app design down the road will be a pain.

5. Costly monolith to microservices migration. Even though microservices prove to be cost-efficient in the long run, migration to this architecture can be very expensive.

The most famous projects implemented with a monolith architecture

The monolith has been a go-to architecture for many decades, and today, it stays relevant due to its benefits, especially for young immature companies. A tech startup is a typical monolithic architecture example because monolith is an easy and reliable architecture to start with. After all, all famous tech companies such as Facebook, Amazon, Uber, and Netflix started as monoliths.

The most famous projects implemented with a microservice architecture

Today, the most breathtaking examples of microservices tech companies are Netflix, Amazon, Coca-cola, eBay, Etsy, and Zalando, but, again, all of them were started as monoliths in the first place. Their monolith-to-microservices migration happened after they outgrew the scalability of their initial monolithic setup. To thrive in the market, they had to pivot towards agility, speed, and flexibility made possible only by the microservices architecture.

How to choose the right architecture?

As you can see from our monolithic vs. microservices architecture pros and cons analysis, neither a monolith nor microservices-based architecture is perfect.

  1. Monolith is easy and cheap to develop from scratch, but it becomes too hard and expensive to scale up and maintain as the application grows. That is why monolith is a good choice for companies at the early stage of application development (when the requirements are not always clearly understood and the MVP needs to be validated ASAP). Go with it if your application is unlikely to grow big in the nearest future.
  2. Microservices address the scalability concerns inherent in monolithic architectures. However, this approach demands a well-coordinated development and operations environment. Transitioning to or starting with microservices requires a solid understanding of service interdependencies and a robust infrastructure for deployment and monitoring. Furthermore, starting as a microservice can be very costly, so before embarking on it, ensure you are up for the challenge.

Monolithic architecture vs microservices architecture: summary

Both the monolith and microservices architecture have strong and weak points you should evaluate based on your current application development situation. For the best outcome, base your choice on things like tech readiness, design and testing results, budget, the development stage, as well as the scalability forecast.