Monolith vs microservices vs serverless

In the world of backend architecture, there are three popular approaches to consider: monoliths, microservices and serverless. Each option has its own set of advantages and disadvantages, so it is important to understand their characteristics and trade-offs. In this article, we will explore the pros and cons of each option and provide a summary of their key features.

Monolith

A monolith is an architecture in which a single service handles all the functionality of a back-end application. It is characterized by its simplicity and ease of development. With a monolith, the development experience is straightforward, allowing for rapid refactoring, bug fixing and feature development. However, scaling a monolith can be challenging because it typically relies on vertical scaling, adding more memory or CPU power to the existing machine. This limitation makes it less efficient at handling increased user load. Monoliths offer low latency and fast performance because there are no additional network calls or service invocations. On the downside, monoliths are prone to single points of failure, where a crash in one part of the application can bring down the entire system. In addition, the cost of running a monolith can be higher because you may end up paying for unused processing power.

Microservices

Microservices involve breaking down a system into multiple services, each with a specific responsibility. This approach allows for greater flexibility and scalability compared to monoliths. In terms of development experience, microservices promote code modularity and strong boundaries between different domains. This makes it difficult to write spaghetti code and encourages clean, compartmentalized code bases. However, infrastructure complexity increases with microservices, as containerization and orchestration tools such as Kubernetes are required to manage and deploy the services. Integration testing can also be more challenging, requiring all services to be spun up together. In terms of scalability, microservices excel because they offer the ability to scale services both vertically and horizontally. They allow independent scaling of specific services based on demand, resulting in efficient resource utilization. Network calls between services can affect Response times in microservices, leading to potential latency issues, especially with large data transfers. On the positive side, microservices offer improved reliability compared to monoliths, as failures are isolated within individual services, minimizing the impact on the overall system. In terms of cost, microservices can be more cost-effective if scaled properly, as you can allocate resources specifically to the services that need them.

Serverless

Serverless architecture, often associated with Functions-as-a-Service (FaaS) offerings, takes a different approach by focusing on the execution of functions in a serverless environment. It allows developers to write and deploy code without directly managing the infrastructure. The experience of developing in serverless environments can be positive, as they offer easy scalability and simplified deployment processes. However, they come with a learning curve as developers must adapt to the serverless paradigm and its specific constraints. Scalability is one of the key benefits of a serverless architecture, as functions can scale automatically based on demand, efficiently handling spikes in user traffic. Response times can vary in serverless architectures, depending on factors such as function cold-start times and potential network overhead. Serverless architectures promote reliability as functions are typically isolated from each other, reducing the impact of failures. In addition, the pay-per-use pricing model of serverless services can result in cost savings as you only pay for the actual execution of functions.

Summary

Choosing the right backend architecture depends on several factors, including developer experience, scalability, response time, reliability and cost. Monoliths offer simplicity and ease of development but can be less scalable, reliable and cost-effective. Microservices offer modularity, scalability and improved reliability but come with infrastructure and operational complexity. Each microservice can be developed, deployed and scaled independently, allowing teams to work on different services simultaneously. This modular approach increases agility and enables faster development cycles.
However, managing a distributed system of microservices requires additional infrastructure and tools. Service discovery, load balancing, fault tolerance and inter-service communication must be carefully implemented. DevOps practices and automation are critical in effectively deploying and managing microservices.
In addition, testing and monitoring become more challenging in a microservices architecture. With numerous independent services, ensuring proper integration and compatibility between them becomes necessary. Testing strategies such as contract testing and service virtualization can help address these challenges. Monitoring tools and practices must be in place to track each service's performance and health and quickly identify and resolve any issues.
So choosing the best solution depends mostly on the requirements, but when we have a new product, the simplest solution would always be a monolith. More resilient to downtime - microservices.