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A Dive into Application Architecture - Part 2 - Monolithic Architecture

Khoa Pham

January 9, 2023

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About the series

Application architecture describes the patterns and techniques used to design and develop an application. Choosing the right application architecture depends on both technical and business requirements. In this series, we will examine the 3 most common application architectures - Monolithic, Software-oriented, and Microservies architecture.In this second part, let’s take a dive into Monolithic architecture.

Introduction to Monolithic architecture

An application is "monolithic" when all its functionalities are contained within a single code base.

In the monolithic approach, all educational concerns are contained in a single large development deployment, and everything from user interfaces to business and database programs is included in the same code base.

The pros, the cons, and the use case of monolithic architecture

Even though monolithic architecture has many drawbacks, it is still one of the finest architectures for small application development.

With all functionalities contained within a single code base, monolithic programs are simple to

  • Build
  • Test
  • Deploy
  • Troubleshoot
  • Scale up

Compared to microservices where professional developers need to discover and construct the services, it is a lot easier to develop.

Pros of monolithic architecture

  • Simple to develop

Any engineering team has the necessary skills and expertise to create a monolithic application as long as it is a common method of developing apps. Hence, it is more straightforward and simpler to construct than microservice architecture.

  • Easier to debug and test

Compared to the microservices model, monolithic programs are significantly easier to test and debug. End-to-end testing can be carried out considerably more quickly because they have a single large code base.

  • Simple to deploy

Simple deployment is another benefit of monolithic programs' simplicity. Monolithic apps just require one code base to be deployed, so there are fewer deployments to manage. Compared to microservices, network latency and security issues are comparatively less of a concern.

Cons of monolithic architecture

  • Trouble with structure understanding

The complexity of a monolithic application increases as it expands. When the structure gets too big, over time, managing it will become a challenge.

  • Difficulty in making new changes

In a system so big and complicated with such tight coupling, it is more difficult to introduce new improvements. Any code change will impact the entire system. This lengthens the total development process considerably. As time goes on, adding new features will become more time and money-consuming.

  • New technology barriers

Introducing a new technology to a monolithic program means redeveloping the entire application, which is quite challenging.

  • Scalability

Monolithic modules cannot be scaled individually, and module separation, as well as independent scaling, are not possible. The only alternative is to grow the entire application. Though it's possible that one of our modules would have higher demand than the others, we still need to expand our application to handle all of our modules.

Communication in a monolithic application

As we are aware, a monolithic program has all of its components running on the same server. Therefore, there is no need for a network call. Therefore, communication between modules in a monolithic application is relatively simple and quick.

Processes can communicate with one another thanks to the inter-process communication feature of the operating system. This suggests that communication occurs through calls to code methods.

Transaction management in monolithic architecture is quite straightforward when compared to microservice architecture. Many frameworks and languages provide transaction management features.

For instance, the entire application is saved in a single database thanks to ORM (software that simplifies processing database records by expressing data as objects, acting as a layer of abstraction on top of the database engine used to store an application's data). They are developed to address scenarios when one context is utilized for all transactions. Therefore, we can simply commit and roll back actions in monolithic systems.

Deploying monolithic architecture

With one single code base, it is more difficult to implement new modifications in a system of this size and complexity with such a tight coupling. The entire system is impacted by each code change.

The entire application must be deployed for even the tiniest update, which is costly and dangerous. The idea that a single problem in one module will bring down the entire monolithic application is unreliable.

As the diagram above shows, a single source code repository receives updates from many huge development teams. Manual testing is needed along the lengthy, challenging, and production-dependent process from code commit to production. Therefore, it follows that the application is big, complicated, unstable, and hard to maintain.


We may claim that the majority of legacy apps are monolithically implemented when it comes to legacy applications. In fact, well-known internet services such as Netflix, Amazon, and even eBay initially had a monolithic architecture.  Monolithic application structure has both pros and cons, and it depends on each scenario or product/project requirements and which tradeoff you choose. In the next article, let’s discover more about Software-oriented application architecture.