Selecting the appropriate architectural pattern is essential at each phase of the software development life cycle. Here are the top 6 crucial software architecture patterns that every architect needs to understand to create resilient and flexible systems:

1. Layered Software Architecture Patterns

The Layered Architecture Pattern is among the most commonly utilized structures in software development. Commonly referred to as multi-layered, tiered, or n-tier architecture, it structures the system into layers, with each layer handling a distinct function. This organization is based on the use of distinct layers—such as presentation, business, and data—each with a specific role and clear separation, which is characteristic of the layered pattern. Usually, applications with a layered architecture pattern most commonly include the following layers:

1. Presentation/ UI Layer: It manages the user interface (UI) and user experience (UX) and communicates with the application layer to process user requests
2. Application/ Service Layer: It acts as a bridge between the UI and the business logic, managing the application workflow
3. Business Logic/ Domain Layer: This layer stores the core business rules and logic of the application and isolates the business logic from UI and data handling concerns.
4. Data Access/ Persistence Layer: It handles data storage, retrieval, and persistence and interacts with databases, file systems, or external data sources.

Nonetheless, the architecture is adaptable, and it doesn’t specify the number and types of layers that must exist in the pattern. In some cases, the business layer and persistence layer are combined into one when persistence logic is embedded within the business layer. So, smaller applications have only three layers, while complicated applications may contain more than five layers. Web applications commonly use the layered pattern to separate user interface, business logic, and data management.

This architectural pattern depends on the concept of layers of isolation. It indicates that changes made in one layer of the architecture will not affect the components in other layers. The layers are independent and have zero to little knowledge of the inner workings of each layer. The layers are closed and help in ensuring isolation. However, in some cases, some layers can remain open, like in the case of adding a shared service layer to an architecture containing common service components.

2. Event-Driven Architecture Pattern

The Event-Driven Architecture Pattern is flexible and very efficient, comprising independent, specialized event processing units that asynchronously handle and process events. The event driven pattern is a common approach in reactive software architectures, enabling asynchronous communication between components, especially in real-time systems and user interface applications. It functions concerning the generation, identification, and use of events, employing either a mediator or broker architecture.

Its approach is based on data that defines events. Events can be anything, like moving the scroll bar or clicking a button, and all the events are processed asynchronously. The components interact by producing and reacting to the events. There are four main characters in this pattern:

• Event Producers: Components that generate events, like the user clicks a button
• Event Consumers: Components that respond to events, like a program that updates the display when the user clicks the button
• Event Channels: Pathways through which the events are transmitted, like simple function calls or complex message queries
• Event Processors: Components that handle the events and execute the logic based on them.

For instance, Unilever implemented the event-driven architecture for their B2B platform, gro24/7, which was struggling to merge different online touchpoints. An event broker connected all the ecosystem applications for direct and middleware communications through the event channel. With intelligent event routing and MQTT protocol for data transfer, the EDA approach decoupled the systems. It allowed real-time data publishing and subscription between applications and touchpoints.

While the event driven pattern enables modular, asynchronous event handling, the pipe filter pattern is another architectural approach that facilitates modular, stream-based processing by passing data through a series of independent filters connected by pipes. Both patterns support modular processing, but differ in how they handle data flow and event communication.

3. Microkernel Architecture Pattern

The major components of the Microkernel Architecture Pattern are a small core system and plug-in modules. The core handles essential functions, whereas plug-ins enhance abilities through specialized processing. This model is perfect for systems that have consistent core functions yet flexible business rules.

This architecture pattern has two major components:

• Core System: Contains the minimal functionality required by the system to run
• Plug-in Components: Contains the additional functionalities that are isolated and run independently from one another, allowing multiple components to operate independently to extend system functionality.

The core tracks the available plug-ins through the registry. When plugging, the registry is updated with information like the name, location, data contract, and contract format of the plug-in. To understand the microkernel architecture, Eclipse IDE is the best example. Eclipse, as a base product, is just an editor; however, added functionalities, like Java Support, Git integration, and debugging tools, make it a more customizable platform.

4. Microservices Architecture Pattern

The Microservices Architecture Pattern divides applications into services that can be deployed independently, enhancing scalability and adaptability. Every microservice can be created, launched, and verified independently, typically accessed through remote protocols, making it suitable to build cloud-native applications. Microservices also enable rapid development and deployment of new features, allowing teams to accelerate updates and respond quickly to changing requirements.

Its structure includes two components: independent services, where each service has a specific role, and communication, where the services communicate with one another using lightweight protocols, like HTTP or messaging queries. Software architecture lays the foundation of robust software, and it refers to the most crucial part of the internal design of the software. A good architecture is important because a wrong architecture pattern can affect software’s performance, and it becomes more expensive to add new features and capabilities in the future.

Software architecture is the highest-level framework, basically the skeleton of the software system. It is the first choice that developers make and upon which the rest of development relies, including the flow of work, code quality, maintenance, deployment, and ease of development.

There’s a reason why software architecture is defined. The identification of all components is essential because they are directly responsible for the success and failure of the software, along with the system created to protect and serve the components. There are different types of software architecture, and every developer should know the essential patterns to streamline the software development and maintenance process. The pattern's benefits in microservices architecture include improved scalability, decoupling of components, and independent deployment, making it a strong choice for modern software systems.

Software Architecture Patterns

Software architecture is the organization of the system. This organization comprises all the components, like organizational structure, behavioral components, and organization of the components into more complex subsystems. It basically addresses how the components will interact with one another, the environment they operate, and the principles used to design the software. Software architecture patterns are applied across various software development contexts to address common design challenges.

Besides, software architecture is not about finalizing a structure for the software, but it is more about the developers’ decisions. These decisions can have a considerable impact on the quality, maintainability, performance, and overall success of the solution within the broader field of software engineering. Here are the decisions that software developer take that affects the overall selection of software architecture:

• Selection of structural elements and their interfaces that will form the system
• The behavior of the elements as specified in the collaboration
• Composition of structural and behavioral elements into the large subsystem
• Architecture’s alignment with business objectives
• Architectural style should guide the organization

The future performance of the software depends on the software architecture decided, as the entire system depends on the choice and implementation of the architecture pattern. It lays the foundation for how the application will handle performance, fault tolerance, scalability, and dependability in the future. For instance, Netflix is based on microservice architecture, which helps the app manage its availability. Salesforce is built on a domain-driven architecture that assists in running the domain logic complexity.

Software development quality attributes play a crucial role in guiding the selection of architecture patterns.

Top 6 Essential Software Architecture Patterns for Every Architect

It is a viable alternative to traditional monolithic architectural patterns, where all application components are tightly integrated into a single codebase and deployed together. Legacy systems often rely on monolithic architecture, which can present challenges for modernization. The architecture organizes several loosely coupled services, so when software architects work with it, it ensures that the message exchanges between them stay backward compatible.

5. Space-Based Architecture Pattern

The Space-Based Architecture Pattern employs distributed shared memory (tuple space) to oversee large-scale applications. It splits the processing and storage across multiple servers. By storing data across multiple nodes, this architecture pattern provides high scalability, fault tolerance, and low-latency data. Space-based architecture is specifically designed to manage distributed components efficiently, making it particularly effective for large-scale distributed systems that require high scalability and fault tolerance.

It provides quick access and reduces the need for expensive disk I/O, which is either overlooked or suggested to promote further decoupling. There are three foundational components:

• Processing Units: These are building blocks where each unit is self-contained and encapsulates the business logic and the data required to act.
• Space: The space is distributed using a shared memory data grid where all the data resides. It is like a central hub where the data is stored, updated, and reviewed.
• Router: The router plays the role of orchestrating the system’s overall functioning. From routing the client requests to the appropriate processing unit to ensure the load is equally distributed, it ensures that every request is processed timely.

A bidding auction website exemplifies this trend effectively. The platform manages bids by logging them, adjusting the top bid, and providing users with information instantaneously.

6. Client-Server Architecture Pattern

The client server pattern is a widely used architecture that organizes applications into separate client and server elements. The client asks for resources, and the server handles the request and replies accordingly. This configuration accommodates various clients and servers, providing communication flexibility. As per this model, all the requests are delivered over a network, and hence, it is also known as the networking computing model.

For example, email systems illustrate this trend. When a user looks for an email, the server fetches and delivers the requested information, improving user experience. There is a three-tier client-server architecture, which consists of:

• Presentation tier, which is the user interface level and manages user interfaces to facilitate user interactions
• The application tier is called the service level
• The data tier comprising the database

The client server pattern is ideal for managing centralized resources such as databases and shared services, making it suitable for systems that require centralized infrastructure for data and service access.

This pattern is suitable for applications that need to scale horizontally and vertically.

Software Architecture Patterns and Their Applications

Here’s a table that explains the use cases of the software architecture patterns:

In addition to the patterns above, other important software architecture patterns include the broker pattern and broker architecture pattern, which are commonly used in distributed systems to facilitate communication among decoupled components. These patterns offer key benefits and numerous advantages, such as improved scalability, flexibility, and dynamic management of system changes. Peer to peer architecture and peer architecture are decentralized network models used for file sharing and messaging applications, where each node acts as both client and server, eliminating the need for a centralized server. The master slave architecture pattern features a master component that manages multiple slave components or slave components, enabling parallel processing and load balancing, which is especially useful in database systems and multitasking applications.

Wrapping Up

Choosing the appropriate software architecture pattern is essential for developing efficient, scalable, and maintainable applications. Selecting the right architecture pattern is crucial for project success, as every pattern, ranging from Layered Architecture to Microservices and Client-Server models, addresses specific requirements and has its advantages and drawbacks. By grasping these patterns, architects can customize their solutions to meet project specifications and future growth.

Whether it’s boosting performance through Event-Driven Architecture or providing adaptability with Microkernel designs, the appropriate architectural decision establishes the groundwork for sustained success in software development. Want to optimize your software architecture types and development workflow? Visit with Hyqoo to hire skilled remote software architects that help you simplify software development.

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