Build Scalable Web Apps with Microservices & DevOps

In the digital era, businesses demand software that is scalable, flexible, and delivered faster. Conventional monolithic designs frequently find it difficult to meet these demands. Build Scalable Web Apps with Microservices & DevOps – Explore how microservices architecture and DevOps practices enable faster, reliable, and scalable web apps.

 To overcome these challenges, two powerful approaches have emerged—Microservices Architecture and DevOps Culture.

While Microservices break down applications into smaller, independent services, DevOps ensures that these services are built, tested, and deployed quickly through automation. Together, they form a strong partnership that enables organizations to deliver high-quality applications at scale.

In this blog, we’ll explore:

1. 1. The difference between Monolithic and Microservices architectures.
2. 2. The advantages of Microservices.
3. 3. How to configure clients, API gateway, and Eureka server for microservices.
4. 4. What DevOps is, and how it supports Microservices.

The relationship between Microservices and DevOps in real-world software development.

Monolithic vs. Microservices

What is Monolithic Architecture?

An application that is monolithic is constructed as a single, cohesive entity. In a single application, the user interface, database access, and business logic are all closely related.

 Example: An e-commerce application where product catalog, user login, cart, payment, and order processing are all bundled in one big project.

Problems with Monolithic Applications:

• • Scalability issues: You cannot scale only one part; you must scale the whole application.
• • Slow development: All developers work on the same codebase, leading to dependency conflicts.
• • Difficult deployments: Redeploying the entire application is necessary for even minor changes.
• • Limited flexibility: Different teams cannot use different technologies easily.

What are Microservices?

An application is divided into a collection of loosely linked, autonomous services using the microservices architecture. Each service can be independently developed, put into use, and scaled to meet specific business needs.

Example (same e-commerce app):

• • User Service → Manages users and authentication.
• • Items Service → Handles item listings.
• • Order Service → Manages orders and payments.

Advantages of Microservices:

1. 1. Independent Deployment → Update one service without touching others.
2. 2. Scalability → Scale only the service that faces a heavy load (e.g., Order Service on Black Friday).
3. 3. Technology Flexibility → Each service can use a different tech stack (Java, Python, Node.js).
4. 4. Resilience: The system does not collapse if a single service fails.
5. 5. Faster Development → Small teams can work independently on different services.

Steps to Build Microservices with Eureka and API Gateway

To understand Microservices in action, let’s walk through the process of building a simple system with three services, a Service Registry (Eureka Server), and an API Gateway.

Step 1: Create Microservices

We’ll build three Spring Boot services:

• User Service (port: 8081)
• Items Service (port: 8082)
• Order Service (port: 8083)

Every service will have its own endpoints and database.

Step 2: Eureka Server (Service Registry)

When you have multiple services, it’s inefficient to hardcode their URLs Eureka Server, which functions as a phonebook of services, can help with that.

• Start a new Spring Boot project for Eureka Server on port 8761.
• Add dependency: spring-cloud-starter-netflix-eureka-server.
• Add @EnableEurekaServer in the main class.

Now, each microservice can register itself with Eureka.

Step 3: Eureka Clients (User, Items, Order Services)

In each microservice:

• Add dependency: spring-cloud-starter-netflix-eureka-client.
• Add @EnableEurekaClient annotation.(in new version doesn’t need)
• Configure application.properties to register with Eureka Server.

Example:

spring.application.name= USER-SERVICE

server.port=8081

spring.datasource.url=jdbc:mysql://localhost/msdb

spring.datasource.username=root

spring.datasource.password=root

spring.jpa.open-in-view=false

spring.jpa.hibernate.ddl-auto=update

eureka.instance.prefer-ip-address=true

eureka.client.fetch-registry=true

eureka.client.register-with-eureka=true

eureka.client.service-url.defaultZone=http://localhost:8761/eureka

Now, instead of calling http://localhost:8082/items, services can simply call:

http://USER-SERVICE/users

Eureka automatically resolves the service location.

Step 4: API Gateway

An API gateway gives clients a single point of entry. Clients communicate with the gateway alone rather than contacting each service separately.

• To use the Spring Cloud Gateway, create a new Spring Boot project.
• Run it on port 8080.

Configure routes in application.properties:

spring.application.name=ms_gatway_app

server.port=8088

spring.cloud.gateway.routes[0].id=USERSERVICE

spring.cloud.gateway.routes[0].uri=http://localhost:8081

spring.cloud.gateway.routes[0].predicates[0]=Path=/u/users/**

spring.cloud.gateway.routes[1].id=ITEMSSERVICE

spring.cloud.gateway.routes[1].uri=http://localhost:8082

spring.cloud.gateway.routes[1].predicates[0]=Path=/i/items/**

spring.cloud.gateway.routes[2].id=ORDERSERVICE

spring.cloud.gateway.routes[2].uri=http://localhost:8083

spring.cloud.gateway.routes[2].predicates[0]=Path=/o/orders/**

eureka.instance.prefer-ip-address=true

eureka.client.fetch-registry=true

eureka.client.register-with-eureka=true

eureka.client.service-url.defaultZone=http://localhost:8761/eureka

Now, the client simply calls:

• /users/register → Redirected to User Service
• /items → Redirected to Item Service
• /orders → Redirected to Order Service

This makes the system more organized, secure, and scalable.

What is DevOps?

While Microservices give us flexibility at the architecture level, DevOps ensures smooth delivery and management of these services at the operations level.

Development (Dev) and Operations (Ops) teams are combined under the technical and cultural approach known as DevOps.

 It emphasizes collaboration, automation, continuous delivery, and monitoring.

Core Concepts of DevOps:

• CI/CD (Continuous Integration & Continuous Deployment) :Automating builds, tests, and deployments.
• Infrastructure as Code (IaC) :Managing infrastructure (servers, networks) with code using tools like Terraform and Ansible.
• Containerization :Packaging microservices with Docker.
• Orchestration :  Managing containers with Kubernetes.
• Monitoring & Logging : Tools like Prometheus, Grafana, and ELK stack.

How DevOps Supports Microservices

Microservices and DevOps complement each other beautifully. Here’s how:

1. Independent Development + CI/CD
   • Each microservice lives in its own Git repository.
   • CI/CD pipelines automatically build and deploy changes to production.
2. Containerization + Scalability
   • Each microservice is packaged into a Docker container.
   • Kubernetes orchestrates containers and scales them automatically.
3. Monitoring + Reliability
   • Microservices generate logs and metrics.
   • DevOps monitoring tools track performance and detect failures early.
4. Automation + Faster Releases
   • DevOps automation ensures microservices can be deployed multiple times a day without downtime.
5. Resilience + Recovery

If one microservice fails, Kubernetes redeploys it automatically.

Real-World Example

• Netflix uses Microservices with Eureka Server and Zuul Gateway.
• With DevOps CI/CD pipelines, Netflix deploys thousands of microservice updates per day.
• This combination gives them agility, fault tolerance, and the ability to handle millions of users worldwide.

So, finally, we can say that Microservices and DevOps are not just buzzwords—they are the backbone of modern software development. They enable organizations to build scalable, flexible, and resilient systems while ensuring faster delivery cycles. When combined, they enable teams to develop quickly, adjust to change, and produce high-caliber software that satisfies changing client demands. 
Applications are divided into smaller, more manageable, and scalable components by microservices.

DevOps provides the automation, monitoring, and collaboration needed to deploy and manage those services efficiently.

Together, they enable businesses to:

• Deliver features faster.
• Scale applications effortlessly.
• Improve resilience and customer experience.

 If Monolithic is like a one-man band struggling to play everything at once, then Microservices + DevOps is like a well-coordinated orchestra, where each instrument (service) plays its part while DevOps conducts the performance.

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Author:- Kiran Tiwari