From Monoliths to Microservices

Hi everyone,

In today's fast-paced tech world, building applications that are scalable, agile, and easy to maintain is more important than ever. As applications grow in size and complexity, developers are constantly looking for better ways to structure and manage their codebases. This has led to a major shift in how software is designed, from the once-dominant monolithic architecture to the increasingly popular microservices approach.

In this blog, we’ll explore the key differences between the two architectures, understand their pros and cons, and learn how this evolution impacts development teams and businesses. So, let’s dive in!

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Life Before Microservices: The Monolithic Way

Consider a large department store under one roof selling everything from groceries to electronics, clothing to furniture. A single team manages this monolithic store, opens and closes as one unit, and any change — like fixing the billing system — requires adjustments across the entire store. That’s how traditional monolithic applications work.

In a monolithic architecture, all components — user interface, business logic, database access, etc. — are tightly packaged into one unit. Everything is developed, tested, deployed, and scaled together. If one small module changes, you have to re-deploy the entire application.

Challenges with Monoliths

While monoliths work fine in the early stages, they become harder to manage as the application grows:

• Tangled Dependencies: Components are so interconnected that updating one might break another.

• Scalability Bottlenecks: You can’t scale a single part of the app (like just the login feature); you must scale the whole thing, leading to increased infrastructure costs.

• Tech Stack Lock-In: You’re bound to one language and framework for everything.

• Deployment Headaches: A small bug in one module can bring down the entire application.

• Slow Releases: Every update requires full application testing, building, and deployment, slowing down continuous delivery.

It’s like replacing a bulb in our department store that requires shutting down the whole building.

Microservices

Now, imagine instead of one big department store, you have a shopping street — each store sells a different product, managed independently. One sells groceries, another handles electronics, and another handles clothing. Each store can open, close, hire staff, or renovate without disturbing the others.

That’s the essence of microservices..

So, What are Microservices?

Microservices architecture breaks the application into small, independent services — each focused on a specific business functionality (e.g., authentication, catalog management, payment gateway). These services are:

• Self-contained

• Loosely coupled

• Independently developed, deployed, and scaled

  

Each microservice can have its database, programming language, and deployment pipeline. It’s all about separation of concerns - one service does one job and does it well.

Common Questions When Adopting Microservices

As exciting as microservices sound, you might wonder:

• How do I split my monolith?
  Break it down by business capabilities — for example, in an e-commerce app like Amazon: product service, cart service, user service, etc.

• How many services should I have?
  There's no golden number. Aim for the “single responsibility principle”: each service should do one thing. One man Army!

  

• But how do services communicate?
  That’s where it gets technical — and interesting.

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Communication Between Microservices

Unlike monoliths, where components talk internally, microservices need a way to speak to each other over the network. There are three main ways this happens:

1. API Calls (Synchronous Communication)

Each service exposes an API endpoint. Other services can send HTTP requests to consume data or trigger actions. It’s like calling a store to ask for their stock availability — you wait for them to respond.

• Example: The Order service calls the Payment service’s API to process a transaction.

2. Message Brokers (Asynchronous Communication)

Instead of direct calls, services can send messages via a broker like RabbitMQ. You don’t wait for a response; you just leave a message.

• Common patterns:

  • Publish/Subscribe: A service publishes a message, and any interested subscriber picks it up.

  • Point-to-Point: A message is sent to one specific service.

• Example: The Inventory service sends a message to the Shipping service when a product is packed.

3. Service Mesh

A service mesh (like Istio or Linkerd) abstracts the communication layer. It handles service discovery, load balancing, retries, security, and observability — without changing the application code.

It’s like a network of smart delivery drones that know exactly which store to deliver a message to, and how to navigate the route.

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Benefits of Microservices

• Tech Stack Freedom: Teams can choose what works best: Node.js for one service, Go for another.

• Faster Development: Teams work independently without waiting for others.

• Fault Isolation: A bug in one service won’t crash the entire application.

• Granular Scalability: Scale only what’s needed — if your search service is heavily used, scale just that.

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Tradeoffs: They aren’t magic!

As much as they solve problems, they introduce new ones:

• Distributed System Complexity: You now have to deal with network latency, partial failures, and debugging across multiple services.

• Communication Configuration: APIs, brokers, authentication, and retries all need careful planning.

• Monitoring and Observability: Tracking logs and metrics across services and servers is harder. You’ll likely need centralized logging (e.g., ELK stack) and monitoring (e.g., Prometheus + Grafana).

When to use Monoliths?

Microservices are awesome, but does that mean monoliths are useless? Nope! When you're just getting the hang of building apps, monoliths are super handy. But as you grow with more users, data, a bigger team, or more traffic (like when users hit your APIs a lot), you might want to start using microservices..

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Final Thoughts

Monoliths are like Swiss Army knives—compact and easy to start with, but difficult to expand as needs grow. Microservices, on the other hand, are like a toolkit—each tool has a specific job and can be improved or replaced independently.

For small teams and simple apps, a monolith might still be the right choice. But if you’re building for scale, speed, and flexibility, microservices open up many possibilities.

The key is knowing when and how to make the transition — and that’s a journey worth planning carefully.

That’s it for this blog! Thanks for reading!

💡Let’s connect! Feel free to reach out:
LinkedIn
GitHub

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