4 Commonly used Software Architectures that you should be aware of as a Software Developer
Published: 2024-01-04 23:54:22

During the development of huge-scale software systems, the team of developers often has to face multiple issues related to scalability, integrity, maintainability, extensibility, cost efficiency and much more. With increasing size, there is a problem of increasing complexity, repository management, coordination and communication. All these factors often enforce the requirements for a well-defined structure which all the team members and the stakeholders of the development process can agree upon. This structure must help the team of developers organize the code in a systematic order, set boundaries within multiple developer teams, and at the same time, make it easier for developers to maintain and extend the codebase for future releases. This is what Software Developers terms as Software Architectures. 

With the rapid increase in software development during the past two decades, industries have come up with multiple software architectures and will continue to develop more architectures as per convenience. However, with the increasing demand for scalability, maintainability and cost efficiency, certain architectures have gained special favourability over others. Today in this blog, we will analyze some of the most important aspects of these favoured software architectures, and help you determine which software development architecture might be the most favourable one for your project.

## Monolithic Architecture

Monolithic Architecture is a more traditional architecture, where all the smaller components and units are interconnected and interdependent. The software being developed is called a Monolith (derived from the geological term ‘monolith' which means a single massive rock), and the whole software system is designed and deployed as one single unit. Like in any traditional software system, this monolith is self-contained, stores and retrieves data from a shared common database, a single API can perform multiple functions, independent from other applications and overall, the codebase remains the same.


![Monolithic Architecture](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/a0gv71kdlkxgip0w1due.png)

Before choosing this software architecture, the developer must know the scope and the size of the software his team is building. Because the monolith software being developed has all of its components present cohesively as one single unit (single-tiered structure), the software module often grows to be one gigantic unit. Furthermore, all the modules and components used while developing the monolith are tightly interdependent. This means, that making a change to a particular module or component might require making changes in multiple modules and components. This often increases the need for documentation, which also has its disadvantages, like reduced time devoted to development and more time devoted to documentation.

Monoliths are known for easier deployment and debugging, with simplified end-to-end testing thanks to it being a single centralized unit. However, it is known to have a slower development speed because of the complexity associated with it, i.e. larger the monolith, the slower the development. And since individual components are interdependent, scaling of individual components is nearly impossible. Unlike in other software architectures, monoliths often support only one technology stack and any technology to the technology stack like programming languages, frameworks and libraries.

Therefore companies often prefer this architecture when the scope and size of the developed software are small and manageable with documented guidance, a consistent technology stack and one major release.

## Service Oriented Architecture

Unlike a monolithic architecture, in a service-oriented architecture the huge monolith application is divided into smaller chunks of self-contained units with a definite business functionality or task process. These units are called services and they are built to be loosely coupled with each other, which means they must have minimal dependencies on each other. The gigantic monolith software or IT infrastructure is broken down into smaller independent and manageable services with its codebase and databases. The services interact with each other using standard protocols like HTTP, SOAP or REST.


![Service Oriented Architecture](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/klu6wyh2qzmzicy01xbw.png)

Each independent service has its unique business purpose and can be developed, deployed and independently scaled. Unlike monolithic architecture, the codebase of each service is isolated from each other and a failure in one service does not result in the overall failure of the application or the IT infrastructure. Because of this, the developers have more freedom to experiment and innovate with new features and roll back if they face any problems. Depending on the requirements, each of the services of microservices can be developed and maintained with a different technology stack and yet be compatible with each other thanks to their loose coupling and communications through well-defined APIs.

Despite having a better advantage than a monolithic architecture, SOA has an enterprise-oriented scope because SOA promotes resource-sharing, enabling the implementation of common data governance standards across different services. Therefore companies usually adopt this mode of architecture when they have to build and maintain enterprise-level IT infrastructures. Some of the examples of SOA can be attributed to all the CRM and ERP applications being used in the market. 

However, what if the scope needs to be increased to the application level? For that, the service granularity, maintainability as well as the speed needs to be increased. For that, we need to look at and analyse the next software architecture.

## Microservices Architecture

Microservices architecture is the most popular and widely used architecture in modern-day IT infrastructure scenarios. It takes a more granular approach than service-oriented architecture, dividing the services into even smaller self-contained services. It came up as a response to counter the limitations of Monolithic Architecture and to provide an application scope rather than an enterprise scope. A large number of companies are now transitioning from a monolithic architecture to a microservices architecture while developing and maintaining applications and IT infrastructures. But in which circumstances should one use this architecture and what are the limitations? Let's find out now.

Similar to service-oriented architecture, in a microservice architecture, the services are further broken down into self-contained units with each service having its distinct business purpose, which too can be independently developed, deployed and scaled by the respective individual developer or team of developers. Each of these independent services has its API endpoints through which it communicates and exchanges data with the other independent services, and as a result, gives the perception of it acting as a single unit.


![Microservices Architecture](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/jl8lzdedi48aszbsjrrb.png)

The focus is on scalability and to have a decentralized architecture where each service is independently developed and managed. Like service-oriented architecture, the codebase of each service is isolated from each other and a failure in one service does not result in the overall failure of the application or the IT infrastructure. Each microservices can also be developed and maintained with a different technology stack without compromising their compatibility. Tools like Docker and Kubernetes play a pivotal role in enforcing microservices architecture by turning these services into distinctive containers.

As each service is developed and deployed individually, there are no issues of downtime or redeployment of the entire IT infrastructure. Microservices architecture does not reduce the complexities of development but instead breaks down complex tasks into more manageable units. It has helped companies to increase deployment speed, reduce cost, and ensure higher performance. Compared to SOA, microservices architecture is also known to be faster, and easier to manage due to its granularity. However, this architecture also has its downsides, like requirements for a new level of communication within the various teams working on different services, and exponential infrastructure costs for each of the microservices. Having a proper management and communication channel is of utmost importance for implementing microservices architecture.

Today with the growing number of users and the increasing demands for scalability, companies like Netflix, Atlassian, Spotify, Uber, etc. all migrated from Monolithic architecture to Microservices architecture and this has helped them keep their huge-scale software systems running without causing any major downtime. This architecture is highly recommended for companies seeking to develop a massively huge IT infrastructure that is more scalable with time, each service having the capacity for hefty functions and ensuring continuous development and deployment.

## Client Server Architecture

Client-server architecture is a software architecture used mostly by web applications. Here the complex tasks and workloads of managing a web or network application are broken down between a server and a client. The server and the client may be present within the same system or may be distinct nodes within the same computer network. The client makes resource or service requests to the server and the server returns the requested resources or services to the client. A server may accommodate multiple clients, and simultaneously exchange 'requests' and 'responds' to all the clients at the same time.


![Client-Server](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/8kcsm1fsyyvt771688j5.png)

In this architecture, the client any mobile or computer application capable of making requests to the server module, and the server is any powerful computer or software application that can process and handle client requests. The communication between a client and a server is established by the client sending an HTTP request to the server. The server then accepts and processes the request, and then responds through the same HTTP request channel. The client-server architecture can be further divided into three sub-types:

1. **Two-Tier Architecture:** In this architecture, the client directly interacts with the server using a standard protocol like HTTP or TCP/IP. This architecture is often used in small-scale applications such as a web application.
2. **Three-Tier Architecture:** Here an intermediate layer between the server and the client is introduced which is called Middleware. The middleware layer contains the logic for handling and prioritizing communications between the server and multiple other clients. This architecture is used in larger and more complex systems.
3. **N-Tier Architecture:** This is an extension of the Three-Tier Architecture, that has more layers for specific functions for scalability and maintainability.

If ensuring scalability and resource sharing (database, files, processing power) between multiple users (clients) despite having centralized management (server module) is the goal, then Client-Server architecture is just the perfect choice for your IT infrastructure or software systems. However, the downside to this architecture is that a failure in the server will bring down the entire system. The complexity involved in setting up the Client-Server architecture is immense and the cost of maintaining a robust server can also be expensive. Therefore it is important to check the business requirements before implementation of this architecture.

Two examples of a Client-Server architecture are Database Management Systems, where users write queries to interact with the servers and Web-based Applications.

So in conclusion, a development project's success greatly depends on the software architecture selected. The monolithic architecture works effectively for smaller projects with clear objectives because of its ease of deployment but difficulties with scalability. Because it allows for resource sharing and modularity, Service-Oriented Architecture (SOA) is a suitable design for IT infrastructures at the enterprise level. Nonetheless, because of its decentralized and granular architecture, microservices architecture has emerged as the standard for contemporary IT infrastructures, allowing for the autonomous creation, implementation, and expansion of services. For scalability and continuous development, businesses like Netflix and Uber have made the switch to microservices architecture with success. Furthermore, the Client-Server architecture and its variations support web applications that need to be scalable, but they come with complexity and cost as well as the danger of a failure of the system as a whole. In the end, the best architecture will depend on the particular requirements, objectives, and scope of the project to ensure flexibility and success in the ever-changing software development industry.