10 Types of Software Architecture Patterns

When designing software architectures, developers often address the same problem over and over again. Here’s when software architecture patterns make the difference, providing reusable schemes that solve common software design challenges. 

Essentially, these patterns provide a set of predefined subsystems that serve as templates for designing the high-level structure of a software architecture. By addressing common concerns like scalability, performance and security, software architecture patterns allow developers to increase their efficiency and productivity. 

During this article, we’ll go through the 10 most popular software architecture patterns, exploring their primary applications and main advantages.

1. Layered (n-tier) Architecture

The layered architecture pattern, also known as the n-tier architecture pattern, is a foundational approach to software design that organizes applications into separate layers, each with a specific responsibility and function.

This pattern is the most common among software architects due to its methods of structuring software applications, offering a clear separation of concerns that enhances maintainability and scalability and a standardized interface that ensures that layers are loosely coupled, making the system more flexible. 

The layered architecture pattern has 4 layers:

• Presentation Layer (UI Layer) – responsible for displaying information to the user and interpreting user commands.
• Business Logic Layer (Service Layer) – contains business rules and logic specific to the application. 
• Data Access Layer (DAL) – provides access to data stored in persistent storage and handles CRUD (Create, Read, Update, Delete) operations).
• Persistence Layer (optional) – In more complex applications, this layer can be added to decouple the way data is stored and retrieved from the data access logic. 

Pros

• The clear division into layers makes the pattern easy to understand and implement.
• Changes in one layer (e.g., swapping out a database) have minimal impact on other layers.
• Teams can work on different layers simultaneously, speeding up the development process.
• Layers, especially the business logic layer, can be reused across different applications.

Cons

• The additional layers can introduce latency, as requests need to pass through multiple layers.
• Over-segmentation can lead to a rigid structure that’s hard to adapt when cross-layer interactions are needed.

Best Uses

The layered architecture pattern is particularly for applications where separation of concerns and development efficiency are priorities. 

• E-commerce Platform
• Banking Application
• Content Management System

2. Client-Server Architecture

The client-server model is a design framework that splits a system into two principal parts: the client, which requests services, and the server, which supplies services. Although it’s possible for both the client and server to reside on the same machine, they typically interact across a network on distinct hardware.

How it works? The process begins when the client sends a request to the server asking for a specific resource or service. Then, the server recipes the request, processes it according to its business logical or operational parameters and prepares an appropriate response. This might involve retrieving data, performing computations, or initiating other actions. The server sends the response back to the client. The response could be the requested data, a confirmation message, or an error message if the request cannot be fulfilled. Finally, the client receives the server’s response and presents the results to the user or passes it to another application component for further processing.

Pros

• By centralizing resources and services on servers, it’s easier to scale up resources or add more servers to meet increasing demand.
• Updates and maintenance can be concentrated on the server side, reducing the need to update client-side software frequently.
• Centralizing sensitive data and business logic on servers allows for more controlled access and security measures.

Cons

• High demand from clients can overload servers, leading to slower response times or system crashes.
• The model relies heavily on network connectivity; issues with the network can disrupt the communication between clients and servers.
• Exposing servers to client requests from the internet introduces security vulnerabilities that must be meticulously managed.

Best Uses

This model forms the backbone of many types of applications, from web applications to email systems, and it is central to the operation of the Internet. 

• Web Applications
• Email Systems
• Online Gaming

3. Microservices Architecture

Microservices Architecture is a distinctive approach to software development and deployment, designed to overcome the limitations of traditional monolithic architectures by breaking down an application into a collection of smaller, independent services.

One of the main concepts in the microservices pattern is the separate deployments of units that create a streamlined delivery pipeline, allowing the easy deployment of microservices and increasing application scalability. 

The microservices architecture uses multiple design patterns: Aggregator pattern, chain of responsibility pattern, API gateway design pattern, branch pattern, and asynchronous messaging design pattern. Each approach offers a way to handle data in order to deliver services.

Pros

• Services can be scaled independently, allowing for more efficient use of resources and improved handling of demand.
• Teams can develop, deploy, and scale their services independently, using the most appropriate technology stack for each service.
• The failure of a single service does not necessarily bring down the entire system. Fault isolation improves overall system resilience.
• Smaller, focused teams can deliver features more quickly and with greater agility, reducing the time from development to deployment.

Cons

• Managing many services and their interactions can be complex. It requires robust monitoring, logging, and coordination mechanisms.
• Ensuring data consistency across services can be challenging, especially when each service has its own database.
• Communication between services over a network introduces latency, which can impact performance if not properly managed.

Best Uses

Microservices architecture is particularly suited for cloud-native applications and organizations aiming for a high velocity of innovation and deployment.

• E-commerce platforms
• Streaming services
• Financial services

4. Event-Driven Architecture (EDA)

Event-driven architecture (EDA) is a design paradigm that emphasizes communication between components through asynchronous events triggered by user actions or data changes.

This architecture pattern is mostly used for applications that require real-time updates, asynchronous processing, or where the components need to be loosely coupled for scalability and flexibility.

How it works? An event is generated by a producer, indicating a change in the system’s state or the occurrence of an action. The event is broadcasted through an event channel, ensuring that it is communicated to interested parties without coupling the producer directly to the consumers. Then, consumers receive the event and process it accordingly. This processing might include updating a database, triggering a new process or generating more events. Depending on the architecture and application logic, the processing of an event might result in specific actions being taken, such as updating a user interface, initiating a workflow, or storing processed data.

Pros 

• Since components communicate through events, they do not need to be directly aware of each other, reducing dependencies and increasing modularity.
• EDA can easily scale to handle high volumes of events and processes.
• New components can be added to the system to listen for and act on events without modifying existing components, facilitating easier updates and expansion.
• The architecture enables real-time processing and responsiveness, as consumers react immediately to events as they occur.

Cons

• Tracking the flow of events and debugging can be challenging in a distributed event-driven system, requiring robust monitoring and logging tools.
• Managing a large number of event types and ensuring they are correctly understood and handled by consumers requires careful design and governance.
• Ensuring consistency across the system, especially in distributed environments, can be difficult when events are processed asynchronously.

Best Uses

EDA is widely utilized in modern distributed systems.

• Stock trading platforms
• Asynchronous systems
• Reactive user interfaces

5. Microkernel Pattern

The Microkernel pattern, also known as the Plug-in pattern, separates the core functionality of a system from its extended functionality and the parts that are likely to change. 

This pattern is designed to encapsulate only the minimal functionality required to get the system started in the microkernel itself, while additional features and capabilities are implemented as separate components, often referred to as plug-ins or modules. 

How it works? The microkernel manages the fundamental operations of the system and provides generic services that are common to various applications. When additional functionality is needed, it can be developed and integrated as plug-ins rather than modifying the core system. These plug-ins can be dynamically added or removed as required. Plug-ins communicate with the microkernel and possibly with each other through the interfaces defined by the microkernel, allowing for a decoupled system architecture.

Pros

• New features or updates can be easily added as plug-ins without affecting the core system, making the system highly adaptable to changing requirements.
• The microkernel itself remains simple and focused on providing only the most essential features, which can simplify maintenance and reduce the risk of system failures.
• The modular nature of the architecture allows plug-ins to be reused across different systems or applications that share the same microkernel.

Cons 

• The additional layer of abstraction between the microkernel and its plug-ins can introduce performance overhead, especially if the communication between them is not efficiently designed.
• Managing a large number of plug-ins and their interactions can become complex.
• Designing a flexible and generic microkernel that can support a wide range of plug-ins without becoming overly complex can be challenging.

Best Uses

Microkernel is suitable for software that requires easy feature expansion.

• Operating systems
• Application software
• Product lines

6. Service-Oriented Architecture (SOA)

Service-Oriented Architecture (SOA) is a software design pattern where applications provide services to other applications via a communication protocol over a network. 

The key concept of SOA is the idea of service abstraction, separating the service functionality from the implementation. SOA services are designed to be loosely coupled, meaning they can operate independently and can be updated without affecting other services or applications that rely on them. 

How it works? Individual services are created to perform specific tasks. These services encapsulate a particular business functionality or process. Services are published to a service registry, which is a directory where services can be found and accessed by other applications. Then, consumer applications or other services search the service registry to find and bind to the services they need. Once a service is discovered, it can be invoked by the consumer application over the network using the service’s interface definition.

Pros

• SOA enables organizations to more quickly respond to changing market demands, as services can be easily combined and reconfigured.
• By promoting the reuse of existing services, SOA can lead to significant cost savings.
• Services can be scaled independently, allowing for more efficient use of resources and improved response times for high-demand features.
• SOA facilitates the integration of diverse systems, both within an organization and with external partners, by providing a common framework for interaction.

Cons

• Designing, implementing, and managing an SOA can be complex, especially in environments with a large number of services.
• The communication between services over a network can introduce latency, potentially impacting the performance of the system.
• Effective governance is crucial in SOA to ensure that services are used correctly, remain secure, and do not become redundant or outdated.

Best Uses

Service-Oriented Architecture offers a reliable framework for building flexible and scalable software systems.

• Enterprise application integration
• Cloud computing
• Business process management (BPM)

7. Model-View-Controller Pattern

The Model-View-Controller (MVC) divides an application into three interconnected components: the Model, the View, and the Controller. This separation is intended to organize the application into distinct sections based on their responsibilities, promoting a clean separation of concerns.

The Model, which is the central component of the pattern, has the application data and core functionality. It’s the dynamic data structure of the software application, and it controls the data and logic of the application.

The View represents the user interface of the application. It displays the data (model) to the user and sends user commands (events) to the Controller. The View is responsible for rendering the data provided by the Model in a format that users can interact with.

The Controller is the intermediary between the Model and the View. It receives user input from the View, processes it, and returns the output display data back to the view. 

Pros

• By dividing the application into three components, MVC inherently promotes organized and modular development. 
• Different developers can work on the Model, View, and Controller in parallel without causing conflicts in the codebase.
• Changes to the business logic, user interface, and control logic can be made independently, reducing the risk of changes in one component affecting others.
• The separation allows each component to be tested independently, improving test coverage and facilitating Test-Driven Development (TDD).

Cons

• Understanding and implementing the MVC pattern correctly can be challenging for beginners due to its division into three components and the interactions between them.
• For very simple applications, implementing MVC can introduce unnecessary complexity and overhead.

Best Uses

MVC pattern is often used in web applications but is applicable to other types of software development as well.

• Web Applications
• Desktop Applications

8. CQRS (Command Query Responsibility Segregation)

Command Query Responsibility Segregation (CQRS) is a software architectural pattern that separates the operations of a system into two distinct parts: commands, which modify state, and queries, which return state.

While small applications can manage both reading and writing to the same database, large-scale, distributed applications necessitate a divided strategy due to their complexity.

How it works? When a command is given to the system, the command side takes over to manage state changes, which includes validating the command, carrying out the operation to change the system’s state, and possibly triggering events to indicate a change in state. Conversely, queries are handled through a different pathway, utilizing a model that is optimized for read operations, often simplified for faster access. The write and read models remain in sync through mechanisms like event sourcing, where alterations in the write model produce events that are used to update the read model.

Pros

• By separating read and write operations, each can be scaled independently based on demand.
• The read and write models can be optimized for their specific purposes. 
• CQRS allows for the use of different storage mechanisms for the read and write sides, depending on what is most appropriate for each operation’s performance and scalability needs.
• Separation of commands and queries can also contribute to more granular security policies, where read and write permissions are managed independently.

Cons 

• Implementing CQRS can introduce additional complexity into the system, particularly in terms of maintaining two separate models and ensuring they are correctly synchronized.
• Depending on the synchronization mechanism between the read and write models, there might be a delay (eventual consistency) before the read model reflects the changes made in the write model.

Use Cases

CQRS is particularly suited to situations where there is a clear distinction between operations that modify state and those that read state, and where these different types of operations have significantly different requirements. 

• High-Performance applications
• Complex systems

9. Serverless Architecture (Function as a Service – FaaS)

Serverless Architecture, particularly in the form of Function as a Service (FaaS), represents a significant shift in how applications are developed, deployed, and managed. It abstracts the complexities of server management away from the developers, allowing them to focus solely on writing the code that powers their applications. 

In a serverless model, the cloud service provider automatically provisions, scales, and manages the infrastructure required to run the application code.

How it works? Developers deploy their function code to a serverless platform hosted by a cloud provider, where the functions are executed in response to specific triggers like HTTP requests, file uploads, or database updates. The serverless platform dynamically sets up an execution environment for the function, runs it, and delivers the outcome. To manage fluctuating demand, the platform automatically scales, creating more instances of the function as needed or deallocating resources when idle, optimizing costs.

Pros

• With micro-billing, you only pay for the compute time you consume, which can lead to significant cost savings, especially for applications with variable traffic.
• Developer Productivity: By removing the need to manage servers, developers can spend more time on building features and improving the application.
• The ability to automatically scale in response to traffic without the need for manual intervention ensures that applications remain responsive under varying loads.
• The cloud provider takes care of the infrastructure, reducing the need for DevOps and allowing smaller teams to manage larger infrastructures.

Cons 

• When a function hasn’t been called for some time, there can be a delay (“cold start”) as the platform provisions a new instance. This can impact performance, particularly for latency-sensitive applications.
• The stateless nature of serverless functions can complicate the architecture of applications that require state persistence across function calls.
• Applications designed for a specific serverless platform may need to be significantly reworked to run on a different platform, leading to potential vendor lock-in issues.

Use Cases

Serverless Architecture represents a paradigm shift in cloud computing, enabling developers to focus more on creating value through their applications rather than managing the underlying infrastructure.

• Web applications
• APIs
• Data processing

10. Peer-to-Peer (P2P) Architecture

Peer-to-Peer (P2P) Architecture is a decentralized network architecture where each participant, or “peer,” acts as both a client and a server within the network. Unlike traditional client-server models, where a centralized server is responsible for processing and managing requests, P2P networks distribute these responsibilities among all peers in the network.

Each peer in a P2P network is equal, sharing resources and services directly with other peers without the need for centralized coordination.

How it works? When a peer joins the network, it connects to other peers, often using a bootstrap process to discover initial contacts. Resources, such as files or computing power, are then shared among peers through direct exchanges. Peers in the network are responsible for resource discovery, data transmission, and network self-organization, dynamically adjusting as peers join or leave. 

Pros

• P2P networks can handle increases in workload and participants more gracefully than traditional centralized systems since additional peers contribute additional resources.
• The decentralized nature of P2P networks makes them more resilient to failures and censorship. 
• By leveraging the collective resources of its participants, a P2P network can reduce the need for expensive infrastructure and bandwidth costs typically associated with centralized services.

Cons

• Ensuring secure transactions and establishing trust between anonymous peers can be challenging. P2P networks are also susceptible to various security threats, including malware dissemination and Sybil attacks.
• Without centralized oversight, controlling the quality and legality of the content shared within the network can be problematic.

Use Cases

Peer-to-Peer Architecture offers a great alternative to traditional centralized systems, promoting scalability and resource sharing.

• File sharing
• Cryptocurrencies
• Content distribution

Enhancing Your App Building Process

The major advantage of using software architecture patterns is their ability to define essential features of your application that result in improvements in the product’s usefulness, boosting the effectiveness of your application development process.

From popular software architecture patterns like the layered architecture or opting for the MVC pattern, there are many different options that are helpful. However, keep in mind that a thorough evaluation of each pattern is essential, as choosing the wrong one can not only cause delays but could result in software failure. 

Besides selecting the right architectural blueprint, make sure your team is equipped with the right workforce to develop reliable software products. If you’re looking to scale your IT team, we’re here to help. 

As an all-in-one recruitment agency and EOR provider, we specialize in connecting your team with skilled software architects who meet your exact requirements, ensuring your project’s success from the ground up. Let’s talk!

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