What is Monolithic Architecture?

‍Monolithic architecture is a traditional approach to software design, where an application is built as a single, unified unit. This method integrates different components of the application, like the user interface, business logic, and data access layer, into a closely-knit package that is deployed as one entity.

• This means if we need to make any changes or updates to the application, we have to modify and redeploy the whole monolith.
  
  
• Monolithic architectures are often praised for their simplicity and straightforward development process, particularly suitable for small to medium-sized applications.
  
  
• However, they can become complex and difficult to maintain as the size and complexity of the application grow.

Advantages of Monolithic architecture

• Simple to develop: Since everything is in one place, it's easier to develop and test the application initially.
  
  
• Simple deployment: Deployment involves deploying the entire application as a single unit, which can be simpler compared to deploying multiple services.
  
  
• Easier to scale vertically: Vertical scaling(upgrading the server’s hardware) can be sufficient for handling increased load initially.

Disadvantages of Monolithic architecture

• Limited scalability: Monolithic applications can be challenging to scale horizontally (adding more instances) as they grow in size and complexity.
  
  
• Tight coupling: Changes in one part of the application can have unintended effects on other parts, making maintenance and updates challenging.
  
  
• Technology stack limitations: You're limited to using the same technology stack across the entire application.

What is Microservice Architecture?

Microservices architecture breaks down the application into smaller, independent services, each responsible for a specific function or feature. 

For example, in an e-commerce application, one service might handle user authentication, another might manage products, and another might handle user notifications or emailing. 

These services are loosely connected and communicate over a network, often using lightweight protocols like HTTP or messaging queues.

Advantages of Microservice architecture

• Scalability: Easier to scale horizontally by adding more instances of individual services, allowing for better handling of increased load.
  
  
• Flexibility: Each service can be developed, deployed, and scaled independently. For example, one service is facing higher demand so we can scale that particular one rather than scaling the entire application. Which can be costly and inefficient.
  
  
• Resilience: Failure in one service does not necessarily affect the entire application, as other services can continue to function.

• Simpler Maintenance: Microservices make it easier to comprehend, update, and maintain the codebase because each service is smaller and concentrates on a specific function. This can result in quicker development and debugging.

Disadvantages of Microservice architecture

• Complexity: Managing a large number of services and their interactions can introduce complexity, requiring careful design and implementation.
  
  
• Communication overhead: Services need to communicate over the network, which can introduce latency.
  
  
• Cost: While microservices offer scalability and flexibility, they can also increase costs, especially in terms of infrastructure and operational overhead. Managing a large number of services can require more resources and investment in tools and infrastructure.

What is Serverless Architecture?

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A serverless architecture — also known as serverless computing or function as a service (FAAS), this software design pattern involves hosting our function (which is a part of the microservice's responsibility) on a third-party platform such as AWS Lambda functions, Azure functions, or Firebase cloud functions. This architecture removes the necessity for developers to manage server software and hardware, as the third-party service handles this automatically.

As mentioned, the responsibility of a single microservice is divided among multiple functions, each of which can be invoked and scaled independently.

Advantages of Serverless architecture

• No infrastructure management: Developers can focus on writing code without worrying about managing servers or infrastructure.
  
  
• Cost-effective: You pay only for the resources used by your functions, making it cost-effective for applications with sporadic or variable workloads.
  
  
• Scalability: Automatically scales based on demand, allowing for efficient handling of varying workloads.

• Rapid development: Allows for rapid development and deployment of code, as there is no need to provision or manage servers.

Disadvantages of Serverless architecture

• Cold start latency: Functions may experience a latency known as "cold start" when they are invoked for the first time or after a period of inactivity.
  
  
• Vendor lock-in: You're dependent on the specific cloud provider's serverless offering, which can limit flexibility and portability.
  
  
• Max run time — for example, an AWS Lambda function can run at least 15m for each execution.

Conclusion

• Monolithic: Suitable for small to medium-sized applications with simple requirements and predictable workloads. Easier to develop and deploy initially but can become challenging to maintain and scale as the application grows.

• Micro services: Ideal for large-scale applications with complex requirements, high scalability needs, and a focus on agility and independence in development and deployment. Offers flexibility but introduces complexity.
  
  
• Serverless: Well-suited for applications with sporadic or unpredictable workloads, or where cost efficiency and rapid development are key. Offers scalability and cost-effectiveness but comes with limitations and potential vendor lock-in.

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