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“Microservices architecture decomposes systems along business capabilities into autonomous Bounded Contexts. A non-negotiable rule is Database-per-Service: each microservice owns its private database. No other service may query its tables directly—all access must cross strict public API/gRPC or asynchronous event interfaces.”
Decomposing monoliths into autonomous Bounded Contexts with isolated private datastores to prevent distributed monolith anti-patterns.
// Order Service - Autonomous Bounded Context with Private Database
import { Router } from 'express';
import { orderRepository } from './db/orderRepo';
import { eventBus } from './events/kafkaProducer';
export const orderRouter = Router();
orderRouter.post('/orders', async (req, res) => {
const { customerId, items, totalAmount } = req.body;
// 1. Write to private isolated database
const order = await orderRepository.create({
customerId,
items,
totalAmount,
status: 'PENDING',
});
// 2. Publish asynchronous Domain Event across service boundaries
await eventBus.publish('OrderCreated', {
orderId: order.id,
customerId,
items,
totalAmount,
timestamp: new Date().toISOString(),
});
res.status(201).json({ orderId: order.id, status: 'PENDING' });
});Identify ubiquitous language and business subdomains (Core, Supporting, Generic)
Draw Bounded Context boundaries separating domain models (e.g. Order vs Inventory vs Billing)
Provision dedicated private database instance per service (PostgreSQL, MongoDB, DynamoDB)
Expose versioned REST/gRPC or GraphQL contracts
Publish Domain Events (e.g. OrderCreated) to asynchronous event brokers (Kafka/RabbitMQ)
Change Data Capture (CDC via Debezium) streams internal database mutations directly into Kafka topics without dual-write race conditions.