Being a software developer, I have worked with multiple types of architecture over the years and with as microservices being all the rage largely thanks to cloud computing and serverless functions, I thought it might help those trying to decide what sort of architecture they should use if I gave a bit of an explainer as to what monolith and microservice architectures are and how to choose the appropriate one for your needs when looking at monolith vs microservices.

There is a lot of buzz in the software industry about the benefits of microservices architecture over monolithic architecture. However, the decision to choose one over the other isn’t as straightforward as it might seem. In this blog post, we’ll discuss the scenarios where a monolithic architecture is a better choice than microservices and vice versa.  Just because microservices is the hot new style, doesn’t mean that is appropriate for every circumstance and can often cause more of a headache than it solves if used in the wrong situation.

Understanding Monolith and Microservices

Before diving into the nuances, let’s briefly define these two architectural styles.

Monolithic Architecture: In a monolithic architecture, all the components of the software application are interconnected and interdependent. In other words, the application is built as one cohesive unit.

Microservices Architecture: A microservices architecture, on the other hand, is an approach where an application is built as a collection of small, autonomous services. Each service corresponds to a specific business functionality and can be developed, deployed, and scaled independently.

When is a Monolithic Architecture Better than Microservices?

There are several instances when choosing a monolithic architecture can be more advantageous:

1. Simplicity and Development Speed

Monolithic architecture is simpler to develop and deploy, as everything operates as a single unit. This makes it a great choice for small-scale applications or startups where the initial focus is on validating concepts and bringing the product to market quickly.  It also makes for considerably less overhead in terms of the mundane DevOps management tasks so you aren’t dealing with multiple build pipelines, settings and security for various services and just all of the stuff that could really be a full time job for somebody.

2. Performance

Since all components of the application reside in the same process, monolithic applications can provide a performance advantage due to shared memory access and the absence of inter-process communication.  Microservices need a means to communicate between services with something like a service bus and that can add an extra layer of processing that can slow things down if you need every bit of possible performance out of the application.

3. Easier Debugging and Testing

Given that the application is a single unit, tracking bugs, and testing is more straightforward in a monolithic architecture compared to a distributed system like microservices.  Having to test a single application rather than the interaction of a bunch of different services makes things a lot easier to figure out where things are going wrong.  Having to jump between projects and have multiple projects running at once to try to track down a bug can be a headache.

When is a Microservices Architecture More Appropriate than Monolithic?

Microservices architecture can be more suitable in the following circumstances:

1. Scalability

When different parts of your application have different scaling requirements, a microservices architecture allows you to scale out the components that require more resources independently.  Being able to throw more resources at a single service rather than an entire application can be a much more efficient use of resources.

2. Complex, Large-Scale Applications

For complex applications with many modules and components, breaking the application down into microservices can make it easier to manage and understand. Each service corresponds to a specific business capability, and different teams can own different microservices.  Breaking down the codebase so that different application functionality can be isolated from other services makes how things work easier to understand, especially when you are bringing on a new developer that is trying to learn the codebase.

3. Diverse Technology Stack

With microservices, each service can use a technology stack that is best suited to its requirements. This provides the flexibility to choose the right tool for each service, and it’s easier to adopt new technologies.  When you transfer information from one service to another over a service bus, it doesn’t matter if the sending service is written in the same tech stack as the receiver and they don’t even have to know about each other.  Its just about knowing how to work with the service bus.

4. Independent Deployments

Microservices can be updated independently of one another. This allows for faster and safer deployments, and you can introduce new features more rapidly without having to redeploy the entire application.  Being able to deploy and test services independently of others makes it a lot faster to deploy changes and not have to worry as much about how the changes might affect other areas in the application.  And being able to deploy changes as they are ready rather than having to wait for a large  deployment of the entire app allows for much faster fixes for things like bugs that show up in production (It happens to all of us!).

In conclusion, there’s no one-size-fits-all answer when it comes to choosing between monolithic and microservices architectures. The right choice largely depends on your specific circumstances, including your team’s expertise, the nature of the project, business needs, and long-term goals. While a monolithic architecture might be a better starting point for small applications, a microservices architecture could be a better fit for large, complex, and scalable applications. As with any architectural decision, it’s crucial to carefully evaluate the pros and cons before making your choice.

If you want to learn more about when these architecture types are applicable, I highly suggest checking out the episode #1856 of the .NET Rocks podcast where they talk all about them.

And just because I like to brag, check out my new software developer t-shirts I scored off of Amazon.