Building Microservices with Cloud APIs

What are Microservices?

Microservices architecture breaks down applications into small, independent services that communicate via APIs. Each service handles a specific business function.

Architecture Overview

In a microservices architecture:

Each service is independently deployable
Services communicate via REST APIs or message queues
Each service has its own database
Services can be scaled independently

Example: E-Commerce Microservices

// User Service
const express = require('express');
const app = express();

app.get('/api/users/:id', async (req, res) => {
  const user = await User.findById(req.params.id);
  res.json(user);
});

// Product Service
app.get('/api/products', async (req, res) => {
  const products = await Product.find();
  res.json(products);
});

// Order Service
app.post('/api/orders', async (req, res) => {
  // Call User Service to verify user
  const userResponse = await fetch(`http://user-service/api/users/${req.body.userId}`);
  const user = await userResponse.json();
  
  // Call Product Service to get product details
  const productResponse = await fetch(`http://product-service/api/products/${req.body.productId}`);
  const product = await productResponse.json();
  
  // Create order
  const order = await Order.create({
    userId: user.id,
    productId: product.id,
    total: product.price
  });
  
  res.json(order);
});

Service Communication

Services can communicate via:

REST APIs: HTTP requests between services
Message Queues: RabbitMQ, AWS SQS for async communication
gRPC: High-performance RPC framework
Event Streaming: Kafka for event-driven architecture

Deployment

Deploy microservices to cloud platforms:

Kubernetes: Container orchestration
AWS ECS/Fargate: Container services
Docker Swarm: Container clustering
Serverless: AWS Lambda, Azure Functions

Best Practices