Monoliths vs Microservices: A Guide to Choosing the Right Architecture for Your Application
Monoliths and Microservices are two different architectural styles for building applications. Monoliths are a single unit of tightly coupled code that includes the client side, server-side, and database code all in one. They are typically used for small to medium-sized applications and can be difficult to maintain, test, and scale. On the other hand, Microservices are a collection of loosely coupled services that communicate with each other via a well-defined API. They are used for large-scale applications that require rapid and frequent development.
Monoliths
In a monolithic application, it can be hard to maintain, scale, and reuse code. The code is all in one place, making it difficult to test and deploy. The overloaded IDE slows down the development process, which ultimately compromises the business. Scaling the company with a monolithic application can be challenging, and continuous deployment is difficult, which goes against the CI/CD culture.
Pros:
Easier to develop and deploy for small to medium-sized applications.
Simple to understand and maintain.
Suitable for smaller teams with limited resources.
Single codebase makes testing and deployment easier.
Cons:
Difficult to scale and maintain as the application grows.
Challenging to integrate new technologies or services.
Changes to one component can affect the entire application.
Higher risk of system failure due to tightly coupled code.
Examples of companies using monoliths:
BT
Wordpress
Shopify (in its early days)
Microservices:
Microservices, on the other hand, offer a highly maintainable and testable application that enables rapid and frequent development. They are independently deployable and scalable, allowing for services to communicate with each other via protocols such as HTTP/REST or RPC. Each service has its own database, making it decoupled from other services. However, with Microservices, there are distributed systems problems to consider, such as inter-service communication and node failures.
Pros:
Easier to scale and maintain as each service is developed and deployed independently.
Highly modular and decoupled, making it easier to integrate new technologies or services.
Increased resilience and fault tolerance due to distributed architecture.
Suitable for larger teams with a need for rapid and frequent development.
Cons:
Increased complexity in development and deployment.
Requires careful planning and design to avoid distributed system problems.
Increased resource consumption due to multiple services running simultaneously.
More challenging to test and debug due to the distributed nature of the application.
Examples of companies using Microservices:
Trainline
Amazon Web Services
Google
Deciding how to partition an application into multiple services is an art in itself. One way to decompose an application into multiple services is by business capability and defining services corresponding to business capabilities. Another way is by domain-driven design subdomains, decomposing by verbs or use cases, or by nouns or resources. Ultimately, each service should have only a small set of responsibilities, similar to the Single Responsibility Principle (SRP) used in class design.
Conclusion
In conclusion, when choosing between monoliths and microservices, it's important to consider the size and complexity of the application. Monoliths work well for small to medium-sized applications, while microservices are better for large-scale applications that require rapid and frequent development. By understanding the benefits and drawbacks of each architecture style and knowing how to decompose an application into multiple services, you can choose the right architecture for your application.