Choosing Server Architecture: Monolith, Microservice, Client-Server or Serverless?

You work in a startup or you’re a business owner looking to ship a product and the software team has finally put together that solution the company wants to take to market but there’s just one hill to overcome and that is knowing which server architecture type to go with in hosting the software products and the trade-offs in doing so. This is an attempt to provide an objective view that’ll hopefully help you in choosing the right server environment for production software applications.

What is a server architecture?

A server architecture is the design or model of a server to accommodate the components, services and roles of which a server is created to render data to nodes that are connected to it.

There are 4 main modern ways to host software applications in server architecture. These architectures provide an environment that meets the needs of the software requirement and design. These environments are the Monolith, Client-Server, Microservice and Serverless architecture.

5 factors to consider for a server architecture.

Before choosing a server architecture it’s important to consider certain critical factors as they will not only help you in budgeting for the right server architecture but will give you insight into what makes each architecture unique.

• Development Experience: Is it easy to refactor, build features and fix bugs?
• Scalability: How many request calls can the server handle per second?
• Latency: How fast is it to respond to request calls?
• Reliability: How does it handle errors or failure in the system?
• Cost: How much does it cost to host per month?

It’s important to weigh how server environments compare by utilizing these 5 factors.

3 common server architecture and how they compare against each other.

Monolith, Microservice and Serverless are the 3 go-to server architecture types with each catering to different needs and use cases. We’ll be looking at each and how they compare against each other based on the 5 factors listed above.

Monolith Architecture

A monolith architecture is built as a single self-contained unit. The entire software application components such as the user-interface, business logic and data access layer are tightly coupled together.

Usability factors:

1. Development Experience

• Simplicity in development as the entire application resides in a single codebase.
• Easy to run unit and integration test on codebase.
• Time from development to deployment for production is fast.
• Can become challenging to manage and maintain as the codebase grows.

2. Scalability

• Can be scaled vertically by amping CPU and memory usage.
• Not feasible for horizontal scaling due to caching, memory and database replication overhead.
• Overall limited scalability due to tightly coupled design of architecture.

3. Latency

• Generally low latency to request calls.
• No internal network calls.
• May experience slow response due poor provisioning and service configuration.

4. Reliability

• Single point of failure; failure can affect the entire application.
• Requires error handling for codebase and service configuration.

5. Cost

• Generally low development and production cost with a fixed price.
• Expensive to scale.
• May result in unutilised paid processing power.

Use Case

Monolith servers are the go-to for business team building small to medium-sized projects with straightforward requirements. The simplicity and quick development in the environment allows for prototyping and releasing MVP (Minimum Viable Product)

Client-Server Architecture

In client-server architecture, the application is split into two parts: The client, which interacts with the user, and the server, which processes requests, performs business logic and manages data.

Usability Factors:

1. Development Experience

• Decoupled control means separation of application concerns and easier maintenance as application grows Can become monolithic if not managed carefully
• Can become monolithic if not managed carefully

2. Scalability

• Generally stable workload due to separation of concerns.
• Parallel processing of frontend and backend services.
• Can result in challenges for certain types of applications.

3. Latency

• Fast response time from client due to separation of concerns.
• Response time from server due to location and load

4. Reliability

• Simplified error handling and debugging.
• No single point of failure; failure from the server doesn’t necessarily affect the client.
• Provides security as server logic isn’t exposed in the client.

5. Cost

• Moderate development and operational cost.
• Scaling challenges may impact cost.

Use Case

Business application with well-defined server-side logic where separation of concern and security is paramount. Best suited for moderate-size projects and development teams.

Microservice Architecture

In a microservice architecture, an application is broken down into small, independent units or services that communicate to each other via an API to handle complex operations. Each independent service is responsible for handling a specific operation.

Usability Factors:

1. Development

• Independent development and deployment of service.
• Increased complexities in managing distributed services.

2. Scalability

• Highly scalable; service can be scaled and optimized independently.
• Supports both vertical and horizontal scaling.
• Parallel processing of services.

3. Latency

• May result in high latency due internal network calls.
• Bigger payload impact response time.
• Generally stable latency.

4. Reliability

• No single point failure; failure in one service doesn’t necessarily impact other services.
• Improved fault isolation.

5. Cost

• Higher development and operational cost (neither good nor bad)

Use Case

Businesses with diverse development teams building large and complex applications with multiple business capabilities with a focus on each specific service adopt the micro-service architecture environment. This allows for independent scaling of service components and provides a continuous integration and delivery (CI/CD) environment where individual services can be updated independently.

Serverless Architecture

Serverless is a cloud-native architecture that allows developers to deploy code as “functions” without managing any servers. The infrastructure is provisioned and managed by the cloud vendor on behalf of the developer.

Usability Factors:

1. Development

• No infrastructure or server to manage.
• Focus on writing abstracted code as functions.
• Limited execution time for functions.

2. Scalabilty

• Scales automatically based on demand.

3. Latency

• Generally high latency due to cold-start function.

4. Reliability

• Highly reliable 
• Fault tolerance provided by cloud provider.

5. Cost

• Cost efficient pay-as-you-go model

Use Case

Best suited for event-driven applications with sporadic workload. Businesses with limited resources looking for a cost-effective solution utilize this environment to prototype and develop small-scale applications.

Conclusion

Choosing the right server architecture or environment for a production software application can be tricky. The first step to it is understanding the solution the application is solving, the system design and the networking requirements. Use the 5 factors stated above as a guide to pick the right server environment that’ll house your software application in production.