Application Architecture: 6 Common Patterns & How to Choose

What Is Application Architecture? 

In software development, application architecture is the process of defining a structure that meets all the technical and operational requirements of an application. It's the blueprint that guides the system's design and delineates how its various components interact with each other.

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The architecture comprises a set of significant decisions about the organization of a software system. It includes choices concerning the software system's structural elements, their interfaces, the integrations between them, and finally, the composition and interplay of these structural elements. All these choices are guided by the system's functionality, resilience, performance, and reusability, as well as by economic and technology constraints.

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Essentially, software architecture is a plan that guides developers in delivering solutions that meet the business's needs while ensuring the application is scalable, maintainable, and adaptable to changing business needs.

Benefits of a Well Designed Application Architecture 

Here are some of the main benefits of a well-designed application architecture:

Reduces Cost by Identifying Redundancies

An application’s architecture plays a critical role in reducing costs associated with software development and maintenance. It achieves this by identifying redundancies in the system. When designing an application architecture, architects map out the system's components and their interactions. In doing so, they can identify any overlapping functionalities, duplicate processes, or unnecessary components that would otherwise inflate the cost of development and maintenance.

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Through this process, architects can consolidate redundant components, streamline processes, and eliminate unnecessary elements, thereby reducing the overall system's complexity. This decrease in complexity reduces the cost of development and simplifies maintenance, further reducing the total cost of ownership of the application.

Improves Efficiency by Identifying Gaps

An effective architecture can improve efficiency by identifying gaps in the system. Gaps could be missing functionalities, inefficient processes, or bottlenecks that hamper the system's performance. By mapping out the system's architecture, architects can spot these gaps and address them during the design phase, long before the application goes into production.

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Addressing gaps early in the process saves significant time and resources, as it's much easier and cheaper to fix issues in the design phase than it is once the application is live. Moreover, a well-designed architecture ensures that the system operates efficiently, providing users with a seamless and responsive experience.

Allows for Interoperable, Modular Systems

A well-designed application architecture makes for a system that is easier to use and maintain. This is achieved by creating an interoperable, modular system where each component functions independently yet can interact seamlessly with others. Such a system allows for smooth integrations, easy upgrades, and straightforward maintenance, as changes to one module do not impact the others.

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This modularity also enhances the usability of the system. Users can interact with the components they need without being burdened by the complexity of the entire system. In addition, if any component needs to be replaced or upgraded, it can be done so without disrupting the entire system, ensuring a consistent user experience.

Software Architecture Pattern vs. Design Pattern

Software architecture patterns, or architectural patterns, provide templates for organizing the high-level structure of a software system. They offer a standard approach to solve recurring design problems. Some common examples of architectural patterns include layered architecture (used in most enterprise applications), event-driven architecture (ideal for real-time data streaming applications), and microservices architecture (perfect for large-scale, complex systems).

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Design patterns are lower-level, reusable solutions to common problems that occur within a given context in software design. They are more about how individual components or modules of a system interact rather than the overall structure of the system. Common examples of design patterns include Singleton (ensures a class has only one instance), Observer (defines a one-to-many dependency between objects), and Factory (provides an interface for creating objects).

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Learn more in our detailed guide to software architecture design (coming soon)

Types and Examples of Software Architecture

Let’s look at some of the different types of application architecture in more detail:

1. Layered or N-Tier Architecture

Layered architecture, also known as N-tier architecture, is one of the most common types of application architecture. In this model, software components are organized into horizontal layers, each with a specific role. Typically, these layers include presentation, business logic, and data storage and access.

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An example of layered architecture is the design of a typical web application. The user interface (UI) forms the presentation layer, the server-side logic forms the business logic layer, and the database forms the data storage layer. This model's benefit is its simplicity and the clear separation of concerns, which aids in system maintenance and expansion.

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However, layered architecture also has its downsides. It can lead to high coupling between layers, making changes difficult to implement. Changes in one layer can affect all layers above it, leading to potential instability.

2. Monolithic Architecture

In a monolithic architecture, all components of the software are interconnected and interdependent. The entire system is one single, unified unit, and the components cannot function independently of one another. All of the app's functions and dependencies are packaged together, which makes the application easy to develop, test, and deploy.

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However, monolithic architectures can be tough to scale and maintain, especially as the size and complexity of the application increase. Moreover, a failure in one component can bring down the entire system, leading to possible service disruptions.

3. Service-Oriented Architecture

Service-oriented architecture (SOA) is an older architecture, still used by some organizations, that is considered the predecessor of microservices architecture. It is a pattern where services are provided to other components via a communication protocol over a network. The basic principle of SOA is to have software components provide services to other components via a protocol that is platform-independent.

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An example of SOA is a banking system where services such as credit card processing, customer data management, and loan processing are exposed as separate services to various consumer applications.

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The advantage of SOA is that it promotes reusability, as the same service can be used by multiple consumer applications. However, it can be complex to implement and manage, and performance can be impacted due to the overhead of service communication.

4. Microservices Architecture

In a microservices architecture, the application is built as a collection of small, independent services. Each service runs in its own process and communicates with others via well-defined APIs.

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Netflix is a prime example of an application built on microservices architecture. Each function, such as user authentication, video streaming, recommendations, and more, is handled by a separate service. This design allows for better scalability and easier maintenance, as each service can be updated or scaled independently.

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However, microservices architecture also presents challenges. It can lead to complex systems and require substantial operational overhead. Furthermore, the need for inter-service communication can result in network latency and data consistency issues.

5. Event-Driven Architecture

In an event-driven architecture, the flow of the program is determined by events such as user actions, sensor outputs, or messages from other programs. Components of the application react to events and produce new ones, creating a continuous, dynamic process.

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An example of event-driven architecture is a real-time chat application. Here, user messages are events that trigger responses from the server and updates to other users' interfaces. This architecture allows for high responsiveness and real-time updates.

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However, managing the flow of events in a complex system can be challenging, and debugging can be difficult due to the asynchronous nature of event-driven architectures.

6. Progressive Web App Architecture

A progressive web application (PWA) combines the advantages of web and mobile applications. PWAs can be accessed via a web browser and offer a user experience akin to a native mobile application.

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Twitter's mobile website is a notable example of a PWA. Users can access it via a web browser, and it offers an app-like experience with features such as offline access, push notifications, and home screen installation.

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PWAs offer the benefit of cross-platform compatibility and ease of maintenance. However, they may not offer the full functionality of native apps, and performance can be impacted due to reliance on web technologies.

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Learn more in our detailed guides to:

• Software architecture tools
• Software architecture example (coming soon)

Key Considerations for Choosing the Right Application Architecture 

Consider the following questions when choosing an application architecture:

What Functionality Is Necessary?

When deciding on the right application architecture for your project, the first thing you need to consider is the functionality required. Every application is designed to solve a specific problem or meet a particular need. So, the functionality of the application will depend on the problem it's designed to solve or the need it's supposed to meet.

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For example, if you’re creating an eCommerce application, some necessary functionalities might include processing transactions, managing customer data, and displaying product information. Each of these functionalities will have different requirements in terms of data storage, processing, and user interface design.

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Therefore, when designing your application architecture, you must consider each functionality individually and think about how they will interact with each other. You will also need to take into account any potential future functionalities. It's often more cost-effective to design your architecture with future expansion in mind than to make significant changes down the line.

How Important Are Performance and Scalability?

Performance refers to how efficiently your application can handle tasks, while scalability refers to the application's capacity to handle increased workloads effectively.

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An application with high performance can handle tasks quickly and efficiently, resulting in a smooth and satisfying user experience. On the other hand, an application that scales well can handle an increasing number of users or tasks without affecting performance.

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When considering performance and scalability, you should think about the expected workload of your application and any potential spikes in activity. For instance, a retail application might experience higher activity during sales events, requiring a scalable architecture that can handle these spikes without affecting performance.

Where Will the Software Live?

The location where your software is hosted is another critical aspect to consider when selecting an application architecture. This could be on-premise, in the cloud, or a combination of both, known as a hybrid solution.

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If you choose to host your application on-premise, you will have more control over your data and infrastructure. However, this option can be more expensive and time-consuming to maintain.

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On the other hand, hosting your application in the cloud can offer flexibility, scalability, and cost-effectiveness. However, it might present challenges regarding data security and compliance.

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A hybrid solution might offer the best of both worlds, allowing you to keep sensitive data on-premise while leveraging the flexibility and scalability of the cloud for other aspects of your application.

How Rapidly Will the Application Evolve?

If you expect your application to change rapidly, you might want to choose an architecture that is flexible and easy to modify.

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For example, a microservices architecture allows you to develop and deploy individual components independently, making it easier to make changes and updates. However, this architecture can be more complex to manage and might not be suitable for every project.

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On the other hand, a monolithic architecture, where all components are tightly integrated, can be simpler to manage but might be harder to modify and scale.

What Is the Skill Level of Your Development Team?

Your team needs to have the skills and experience necessary to design, develop, and maintain the architecture you choose. For instance, a microservices architecture might require a team with experience in distributed systems and containerization technologies. On the other hand, a monolithic architecture might require a team with strong skills in a specific technology stack.

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In a matter of a few clicks, CodeSee creates a visual map of your codebase’s dependencies. With every merged PR, CodeSee automatically updates the diagram, making it as much a source of truth as your code itself. 

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Our platform is designed to seamlessly integrate with your software development workflow, offering a range of tools and features to streamline your architectural processes:

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Interactive Diagrams: Create visually interactive software architecture diagrams effortlessly. With our drag-and-drop interface, you can design and document your architecture with precision and clarity.

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Real-time Collaboration: Collaboration is at the heart of successful software architecture, and CodeSee makes it a breeze. Work collaboratively on architecture diagrams in real time, allowing your team to brainstorm ideas, spot potential issues, and make informed decisions together. Say goodbye to version control headaches and communication gaps.

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Code Understanding: CodeSee goes beyond static diagrams. Our platform provides code-level insights directly within your architecture diagrams. Visualize code dependencies, identify performance bottlenecks, and ensure your architecture aligns with your codebase.

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Learn how to visualize your software architecture with CodeSee