What's the best Enterprise Software Architecture style for your project?

While I am a fan of Microservices Architecture, I also believe they can be overprescribed. A well-designed "monolithic architecture" following SOLID principles and good patterns will be still be easier to maintain and debug than a microservice one. I think the bad rap monoliths received is when they were poorly designed and implemented - which is not the fault of the architecture.

The best enterprise software architecture style depends on the project requirements, but generally, microservices architecture is preferred for its scalability, flexibility, and ability to support continuous deployment. It allows independent development, testing, and deployment of services, enhancing agility. Alternatively, service-oriented architecture (SOA) can be used for integrating diverse applications within an enterprise, while event-driven architecture is ideal for systems needing real-time data processing and responsiveness. Layered architecture is also commonly used for its simplicity and separation of concerns.

Lesson: In today's unpredictable business environment think hard about scaling. When I built applications in the mid-90s, the only option was Monolithic. One project involved creating a portal for the first live-streaming event ever (WCW wrestling). Client speck'd it for no more than 500 users, so we built a single server application, tested it well, and were confident it would handle it. About 500 signed up hours before the event. At the last minute, new users piled in, resulting in several thousand. Our team desperately worked to add additional servers, as users logged on to watch the event. We could not keep up with the demand. The entire cluster slowed to a halt. What could have been a successful event turned out to be a disaster.

Monolithic architecture entails a unified codebase where components like UI, business logic, and data access are tightly interwoven, executing in one process. Its singular nature simplifies development, testing, and deployment, eliminating component communication complexities. However, this design can impede granular scalability, complicate CI/CD, and magnify bug impacts, leading to potential system-wide failures. The lack of compartmentalization also complicates debugging. Ideal for projects with static requirements, monoliths may falter in multi-platform or highly scalable environments.

Reminds me of X with Desantis announcement. Demand validation ahead of time is not always accurate. As more events move to social based platforms, demand volatility has to be addressed by the underlying technology.

In addition a microservice architecture supports a Devops Model where the dev team olso takes care of the production operation of the service.

Following my comments on monoliths above, I do believe the Microservice Architecture is essential for projects which are either complex in functionality or will have high scale requirements. They are superior to monoliths when it comes to scaling, managing deployments over time, and flexing into future technologies. They end up forcing separation of concern and "SOLID-like" principles, which can make them appear better architected than a monolith which doesn't force these design decisions.

Microservices architecture decomposes applications into independent, loosely coupled services, each governing its distinct domain and tech stack. Services interact via interfaces like RESTful APIs or message queues. This structure supports parallel development, flexibility, and resilience. Yet, it adds complexities in service discovery, coordination, and monitoring, alongside heightened network latency. Amazon exemplifies this approach, with AWS providing tools to manage these complexities. Microservices cater to evolving projects, especially when multi-platform adaptability is essential.

This strategy is sound, however its applicability will vary based on the kind of product model. Since not all services are required at once, it's perfect for applications with lots of features, like AI-driven models. It might not be appropriate to utilize this in banking or finance. But I like it because it's flexible, adaptable, and simple to scale up.

Amongst other benefits like world scale apps , this type of architecture allows for rapidly changing requirements, multiple versions of a service for backwards compatibility to meet needs of various clients release schedules and supports container deployments for infrastructure mgmt.

I still remember my excitement, more than 20 years later, when I learned about n-tier architecture over the 2- then 3-tier architectures which we were building for web applications. n-tier is the grandparent of microservices (with Service-oriented Architecture being the middle of the lineage). n-tier absolutely introduced complexity and redundant code early on - but also, for complex systems - focused specialization of concerns. In enterprise systems, this made all the difference of testing and scaling, when powered by contract-based development.

Layered architecture is akin to an orchestra: distinct sections harmonizing for a collective outcome. The presentation layer sets the user-interaction rhythm, the business layer forms the core logic melody, and data access handles data flow dynamics, while cross-cutting layers add nuanced instruments like logging. These layers, with clear boundaries, communicate through defined contracts, emphasizing modularity. This approach enhances maintainability and testability. However, as in orchestras where added sections can affect tempo, more layers can introduce redundancy and performance challenges. Suited for projects with set requirements on a single platform, this architecture harmonizes structure and function.

My first event-driven architecture was around 10 years ago, and became the integration backbone of a complex system of systems. Previously, each system had to integrate directly with any other, creating a spaghetti mess of system dependencies. By flipping to event-driven, each system was only responsible for communicating out its relevant business events, and subscribing to ones which it cares about. This led to an Enterprise Service Bus for communicating all the events, and allowed any new services to participate without impacting any existing systems. Also - I think Microservices and Event-Driven should always go hand-in-hand - it's hard to have one without the other.

I’m my experience Event Driven architecture maps more seamlessly to actual business workflow. The end of a specific workflow triggers the beginning of another until the process is complete. With virtualization and actual transformation of hardware into logical units, mapping and more important scaling is made possible with minimum amount of disruption. Also, scaling is right-sized and focused to actual need compared to previous method of generally scaling up everything, which results in wastage of resources.

Event-driven architecture functions like a sophisticated relay race: events, symbolizing system changes, are passed between participants. Initiated by sources like sensors or user actions, these events relay through brokers such as message buses before being consumed by processors for actions or transformations. This relay is reactive, scalable, and ensures decoupled interactions, facilitating dynamic interplay and distributed event management. As a relay can face baton-passing complexities, this architecture can grapple with event tracking, increased network traffic, and potential latency. Tailored for high-velocity, real-time data projects across diverse platforms, this approach thrives where immediacy and adaptability intersect.

A Serverless architecture is on option for an deployment of a microservice architecture or a very tiny Monolithic app. It’s more an deployment option than an software architecture

Once you have an event-driven architecture, you should think about the actions which need to happen based on the events. Send an email? Refresh a data warehouse? There are many operations occurring because of an event. Serverless architecture becomes a natural host for such actions. The code should be simple and have no external dependencies. It can be stateless. Because its serverless, you are only paying for compute when events are happening. When things are quiet, your costs are low. So your cost is just as elastic as your activity. By combining all of these architectures (serverless, microservice, event-driven, layered) you can come up with a highly scalable system with very little fixed infrastructure.

When thinking about the best architecture for an enterprise system one would need to go back to first principles to boil down the needs to a concise set. There is not a single approach that works for all usecases. Consider a case where one is building an enterprise feature to quickly get it into the hands of user, in this case optimizing for time to market would be at most importance. If one is building a feature into a larger flow/system that is critical to a business process then considering the architecture that is "build to last" would be key. In short, the right architecture for your enterprise software will depend on your situation and the specific usecase.

Microservices, though flexible and scalable, introduce complexity in service coordination. Layered architectures are modular and maintainable but can suffer from performance degradation and redundancy.

The best architecture style for a particular project will depend on the specific requirements and constraints. However, the following factors should be considered when making the decision: Scalability: The architecture should be able to scale to meet the needs of the project. Performance: The architecture should be able to perform well under load. Security: The architecture should be secure and protect the data. Maintainability: The architecture should be easy to maintain and update. Usability: The architecture should be easy to use for the end users.

Architectural style has evolved with Technologies capability and it's endless applications. Its the organization's Capability Maturity that is key to the success or failure of whatever style you choose. This maturity is typically dictated by external factors which drive the organizations behavior. So when you are deciding on the best style, consider the organization and the problem domain.