Learn how to implement Microservices Architecture with NestJS in this detailed guide. Discover the benefits of microservices, how to set up NestJS for microservices, and best practices for building scalable, reliable applications. Plus, get interview questions and company examples!
Imagine you have a huge toy factory that makes thousands of toys every day. Instead of having just one big machine that does everything—like designing, painting, assembling, and packaging—you decide to break it into smaller machines. Each machine will do one specific job really well. One machine paints the toys, another assembles them, and another does the packaging. These machines can work independently, but they communicate with each other to make sure the toys are made on time. This is very much like Microservices Architecture in software development.
In the world of software, a microservices architecture is a way of building big applications by splitting them into smaller, independent parts. These smaller parts (called “microservices”) each focus on one task and can work on their own, but they still talk to each other to form a complete application.
NestJS is a tool that helps developers build these small, independent services in a clean and efficient way. In this blog, we’ll explain what microservices are, how to implement them with NestJS, and why they are so powerful for building large applications.
Table of Contents
What is Microservices Architecture?
Microservices is a style of software design where an application is split into many smaller, self-contained services. Each service focuses on a specific business task or function. These services can work independently, but they communicate with each other over the network to form a complete, functioning application.
Imagine you’re building a toy factory again. Instead of having one big machine that does everything, you have different machines for each step:
- Machine 1: Designs the toys.
- Machine 2: Paints the toys.
- Machine 3: Assembles the toys.
- Machine 4: Packages the toys.
Each machine is good at its job, and if one machine breaks down, only that specific task is affected, not the whole factory. Similarly, in microservices, if one service goes down, the other services can keep working, which makes your application more reliable and easy to fix.
Why Use Microservices?
Microservices come with several advantages:
- Independence: Each service can be updated, scaled, or fixed without affecting the others.
- Flexibility: You can use different programming languages or databases for each service.
- Scalability: You can easily scale individual services based on their needs, making the system more efficient.
But, like any good thing, microservices also have their challenges. They need to communicate well with each other, manage data properly, and make sure everything works smoothly across all services.
What is NestJS?
NestJS is a framework built with TypeScript for building efficient and scalable applications. It is inspired by Angular and helps developers create well-structured, easy-to-maintain applications, especially microservices.
Think of NestJS like the blueprint for building your toy factory. It tells you how to set up all the machines (services) in a way that they can work together in harmony. NestJS is particularly great for building microservices because it has built-in tools to make it easier to break down your app into smaller parts, handle communication between them, and manage their data.
How to Implement Microservices with NestJS
Now, let’s walk through how you can build microservices using NestJS. We’ll use a simple example where we have a Toy Store Application. We’ll break it down into three microservices:
- Toy Service – This will handle toy data (like toy names, prices, etc.).
- Order Service – This will manage orders (like placing an order for toys).
- Payment Service – This will handle payment processing.
Each of these services will run independently, but they’ll communicate with each other to make the app work.
Step 1: Setting Up NestJS
First, you’ll need to install NestJS in your project. You can do this using npm (Node Package Manager):
npm i -g @nestjs/cli
nest new toy-store
This creates a new NestJS project with the basic folder structure set up for you.
Step 2: Creating the Services
For each of our services (Toy Service, Order Service, and Payment Service), we’ll create different modules and controllers in NestJS. Each service will have a different job, but they’ll be able to communicate through a method called HTTP Requests or Message Brokers.
Here’s how you would create the Toy Service:
nest g module toy
nest g controller toy
nest g service toy
You would repeat this process for the Order Service and Payment Service.
Step 3: Setting Up Communication
Now, we need to connect these services together. In a microservices architecture, we typically use message brokers or HTTP communication for the services to talk to each other.
NestJS makes this easy by providing built-in decorators like @MessagePattern for message-driven communication or @Get() for HTTP communication. For example, when the Order Service wants to get the available toys, it will send a message to the Toy Service, asking for the list of toys.
// Toy Service
@MessagePattern('get-toys')
async getToys() {
return this.toyService.findAll();
}
And in the Order Service, you would call the Toy Service:
// Order Service
@MessagePattern('get-toys')
async getToys() {
return await this.client.send('get-toys', {});
}
Step 4: Running the Microservices
Each service (Toy, Order, and Payment) will run as its own process. They can be deployed independently, which makes the system more flexible. You can even scale up services that need more resources, like the Payment Service, during a busy time, without affecting the Toy Service.
Benefits of Using Microservices in NestJS
- Separation of Concerns: Each service has its own responsibility. The Toy Service only handles toy data, and the Order Service handles orders. This makes it easy to manage and maintain.
- Scalability: You can scale up each service independently. For example, if more people are placing orders, you can scale up the Order Service without affecting the other services.
- Fault Isolation: If one service breaks, the others can continue working. For example, if the Payment Service goes down, customers can still browse and place orders.
Interview Questions on Microservices with NestJS
If you’re preparing for a job interview and you think you’ll be asked about microservices with NestJS, here are some common questions:
- What are microservices, and why are they used in software architecture?
- This question checks your understanding of the core idea behind microservices.
- How does NestJS support building microservices?
- Be ready to talk about how NestJS can be used to structure microservices and how its decorators like
@MessagePatternwork.
- Be ready to talk about how NestJS can be used to structure microservices and how its decorators like
- How do microservices communicate with each other?
- You should know that microservices communicate through HTTP requests, message brokers, or events.
- What are the advantages of using microservices over monolithic architecture?
- This is to check if you know the scalability, fault tolerance, and flexibility benefits of microservices.
- How would you handle failure in a microservices architecture?
- You should mention things like retries, fallback mechanisms, and circuit breakers to handle service failures.
Companies That Have Asked About Microservices with NestJS in Interviews
Many companies use microservices for building large-scale applications, and NestJS is a popular framework for implementing them. Some companies that have asked about microservices and NestJS during interviews include:
- Tata Consultancy Services (TCS)
- Cognizant
- Infosys
- Accenture
- Wipro
- Amazon
- Netflix
- Capgemini
These companies are known for working on large-scale distributed systems, and knowledge of microservices architecture, along with frameworks like NestJS, is highly valuable.
Conclusion
Microservices architecture is a great way to break down a large application into smaller, independent services that communicate with each other. NestJS is a fantastic tool for building microservices in an organized and efficient way. Whether you’re creating a small toy store application or a massive e-commerce platform, using microservices with NestJS can help you create a scalable, flexible, and easily maintainable system. So, next time you build an application, think of it as a collection of small machines working together to get the job done!