Speaker 1: Software architecture is to applications what foundations are to buildings. Build it wrong, and no matter how beautiful it looks, it will crumble. In today's discussion, we'll unpack some prevalent software architecture patterns that form the backbone of countless applications and platforms we interact with daily. Over the next few minutes, we'll explore five key patterns that have shaped the industry. Let's start with layered architecture. This pattern separates the components of a system into distinct layers, typically the presentation layer, business logic layer, and data access layer. For instance, in user interface design, we often see the model-view-presenter pattern is a specialized form of layer architecture. Where the model represents data and business logic, the view displaces data, and the presenter serves as a bridge to ensure a clean separation of concerns. The primary goal of layered architectures is to promote separation so changes in one layer don't negatively impact others. This structure provides abstraction and encapsulation, with each layer having a distinct responsibility. Next is event-driven architecture. This pattern promotes the production and consumption of events between loosely coupled software components and services. Components broadcast events when something notable happens, and other components subscribe to specific events they are interested in. This allows for highly decoupled architectures. One prominent example in this domain is CQRS. With CQRS, the data write operations, commands, are separated from read operations, queries, and changes are often communicated through events. This makes the system inherently event-driven. The PubSub model, where components publish and subscribe to events, is commonly used in such architectures. Software components don't call each other directly, they merely react to published events. Moving on to microkernel architecture. This pattern emphasizes separating core system functionalities into a small microkernel and extended functionality into add-ons or plugins. In operating systems, for example, a microkernel might oversee vital tasks like inter-process communication while offloading other system functions to external components. An application example is the Eclipse IDE. Its core runtime handles the plugin architecture, and features from Java tools to Git integration are delivered as plugins. This design prioritizes extensibility, ease of maintenance, and fault isolation. Whether it's an OS component or an Eclipse plugin that encounters an issue, the core system remains stable and unaffected. Then we have microservices architecture. This decomposes an application into a collection of small, loosely coupled services. Each service implements specific business capabilities, contains its own data model, and communicates via APIs. Netflix, for instance, uses microservices to handle everything from movie recommendations to billing. This architecture promotes modularization of functionality, so services can be developed, deployed, and scaled independently. It increases agility and allows companies like Netflix to rapidly innovate. The trade-off, however, is the added complexity in managing inter-service communication and maintaining data consistency. Last but not least, we have monolithic architecture. At its core, a monolithic design sees all components of an application, from data, access and business logic, to the user interface, bundled together into a single codebase and run as a single unit. This approach simplifies development and deployment, making it a go-to for many startups and smaller applications. However, it's worth noting the rise of the modular monolith. This approach retains the benefits of a single, deployable unit, but emphasizes clear modular boundaries within the codebase. This allows for easier maintenance and scalability. It's a middle ground which offers the simplicity of a monolith while paving the way for potential future transitions to architectures like microservices. Regardless of the approach, many successful platforms start with a monolithic or modular monolithic structure before considering more distributed architectures. And there you have it, a quick tour of five foundational software architecture patterns. The right choice always depends on our specific challenges, requirements and contexts. So which patterns resonate with you? Drop a comment below and let us know which architecture patterns intrigue you the most. If you like our videos, you may like our system design newsletter as well. It covers topics and trends in large-scale system design, trusted by 500,000 readers. Subscribe at blog.bytebytego.com