Monolithic Application Architecture
A monolithic application architecture, or monolith, is essentially one large piece of source code with countless dependencies within it. You can metaphorically think of a monolithic application as one big, heavy stone. Just like it’s hard to move and change the position of a large stone, it’s the same with monolithic applications - every update and change can pose enormous challenges for deployment into production.
Disadvantages of Monolithic Architecture
- Slow Response to Market Changes: Even if PHP and Java seem to "rule the world" today, they might not tomorrow. A new and better programming language may emerge. Your monolith could become outdated, and finding a developer willing to sift through the old code to understand and rewrite your application can be time-consuming and costly.
- Business Limitation by Application: Imagine your application becomes a success overnight, attracting thousands of users worldwide. At that moment, "it starts to slow down." Increasing the throughput of a monolithic application is difficult when faced with unexpectedly high user access.
- Prone to "It Just Doesn't Work" States: Due to the rigid dependencies within a monolith, releasing a new version of the application carries a high risk of breaking something with even minor modifications. This risk is further increased if testing is underestimated or omitted entirely.
When to Use a Monolith?
From the disadvantages above, it might seem that monolithic applications no longer have a place in the market, resembling a dinosaur among architectures. However, monoliths are suitable for small, simple projects where it's certain that the user base is not demanding in terms of functionality and is relatively small.
Microservice Architecture
Microservices are the direct opposite of monoliths. Metaphorically, imagine breaking that large stone into gravel. You can easily shovel just as much gravel as you need for your purpose. It’s the same with microservices. Need to update the part of the application that handles notifications? No problem! You can upgrade just the notification service without impacting any other part.
Advantages of Microservice Architecture
- Code and Responsibility Segmentation: The entire application is composed of smaller sub-applications. For instance, one sub-application handles user login and registration, another handles email sending, another communicates with the bank for payment verification, and another sends phone notifications. A failure or breakdown in one sub-application does not cause the entire system to collapse.
- Independence from Programming Language: A new microservice can be developed in a completely different programming language than the rest of the application. This allows the application to adapt dynamically to the programmer market (you won’t need just Java developers; if they are scarce, you can hire Node.js or Go developers). Similarly, the application can dynamically adapt to or even create trends in the IT world.
- System Scalability: Microservice architecture is much more flexible than monoliths. If, for example, the email-sending sub-application is overwhelmed, it can run on more servers, with the application evenly distributing the load, preventing the user from feeling "it’s slow."
- Independent Development Teams: Each microservice can be developed by a completely different team. Microservices are independent and communicate through clearly defined interfaces. This allows work to be distributed anywhere and to anyone.
- Ease of Testing and Automation: Due to the code being divided into smaller logical units with clearly defined functions and responsibilities, the testing process is simplified. This results in easy automation and quick feedback on any errors introduced into the application.
- Frequent and Simple Updates: Since each microservice is independent, new versions can be released multiple times a day without jeopardizing the rest of the application.
Disadvantages of Microservice Architecture
Despite its numerous benefits, microservice architecture also has a few drawbacks. To ensure a microservice architecture functions properly, it’s essential to have a team expert who understands it. This role is not suitable for junior programmers, as it requires certain skills and experience with such development.
