🛍️ Bazaar — Polyglot Microservices Based E-Commerce Platform

⚡️ Overview

Bazaar is a next-generation, microservices-based e-commerce platform built using multiple frameworks and databases, all orchestrated with a Turborepo monorepo. It demonstrates real-world distributed architecture — event-driven communication, polyglot persistence, and framework interoperability.

🧠 The goal: showcase how different technologies (Express, Fastify, Hono, Next.js, Kafka, Stripe, Clerk, etc.) can cohesively form a modular, scalable, event-driven e-commerce system.

📘 Data Flow

                        ┌────────────────────┐
                        │     Web (Next.js)  │
                        └─────────┬──────────┘
                                  │
       ┌──────────────────────────┼───────────────────────────┐───────────────────────────┐
       ▼                          ▼                           ▼                           ▼
┌──────────────┐          ┌──────────────┐            ┌────────────────┐           ┌─────────────────┐   
│ Product Svc  │──Kafka──▶│ Order Svc    │──Kafka─ ─▶│ Email Svc      │──Kafka──▶│ Payment Svc     │──Stripe Webhook──▶ Payment Success
│ (Express +   │          │ (Fastify +   │            │ (Worker + Kafka│           │ (Hono + Stripe  │
│ PostgreSQL)  │          │ MongoDB)     │            │ Consumers)     │           |  )              |
└──────────────┘          └──────────────┘            └────────────────┘           └─────────────────┘
       ▲                          
       │                          
       │         
       │         
       │  
       │ 
       │  
       │  
       │
       ▼
┌──────────────┐
│ Auth Svc     │──Clerk API──▶ User Authentication
└──────────────┘

🧱 Project Structure

bazaar/
├── apps/
│   ├── web/               # Next.js storefront (user-facing)
│   ├── admin/             # Next.js admin dashboard
│   ├── product-service/   # Express + TypeScript + PostgreSQL (via Prisma)
│   ├── order-service/     # Fastify + TypeScript + MongoDB (via Mongoose)
│   ├── payment-service/   # Hono + TypeScript + Stripe integration
│   ├── auth-service/      # Express + TypeScript + Clerk authentication
│   └── email-service/     # Kafka consumers for transactional emails
│
├── packages/
│   ├── kafka/             # Kafka setup (producer/consumer utilities)
│   ├── product-db/        # Prisma + NeonDB client
│   ├── order-db/          # Mongoose + MongoDB connection
│   └── types/             # Shared TypeScript types across services
│
└── turbo.json

⚙️ Services Overview

Service	Framework	Database	Description
🛒 Product Service	Express	PostgreSQL (via Prisma)	Manages products, CRUD ops, and publishes Kafka events
📦 Order Service	Fastify	MongoDB (via Mongoose)	Handles order creation/retrieval, consumes & emits Kafka events
💳 Payment Service	Hono	—	Integrates with Stripe APIs and webhooks for payment flow
👤 Auth Service	Express	Clerk	Manages user retrieval and authentication
✉️ Email Service	Node (Kafka Worker)	—	Subscribes to user.created & order.created for emails

🌍 Frontend Applications

App	Framework	Purpose
🏪 Web App	Next.js	Customer-facing storefront (products, checkout, etc.)
🧑‍💼 Admin Panel	Next.js	Dashboard to manage products, orders, and payments

📦 Shared Packages

Package	Purpose
🧭 kafka	Central Kafka setup and utilities
🧩 product-db	Prisma + NeonDB connection for product data
🧱 order-db	MongoDB connection and Mongoose models
🧾 types	Shared TypeScript types between services

🧠 Design Philosophy

• 🧩 Polyglot Microservices: Each service uses a unique framework and database.
• ⚡ Event-Driven Architecture: Kafka enables async communication and decoupling.
• 🧰 Turborepo Monorepo: Enables isolated builds and shared dependency management.
• 🔒 Decoupled Auth: Clerk ensures secure authentication across apps.
• 💳 Modern Payments: Stripe webhook for checkout.session.completed event.

🧰 Local Development

# Clone the repo
git clone https://github.com/muditkalra/microservices-ecommerce.git
cd microservices-ecommerce

# Install dependencies
pnpm install

# Start Kafka  (via Docker Compose)
cd packages/kafka
docker compose up -d

# Run a specific service (example: product-service)
pnpm --filter product-service dev

# Or run all apps & services
pnpm run dev

⚠️ Configure .env files for each app (Stripe, Clerk, databases, etc.) before running.

📈 Future Roadmap

• API Gateway / GraphQL BFF
• Redis caching layer
• gRPC inter-service communication
• Prometheus + Grafana monitoring
• CI/CD with GitHub Actions
• Background worker optimizations

⚙️ Tech Stack Summary

Layer	Technologies
Frontend	Next.js (App Router, TypeScript)
Backend	Express, Fastify, Hono
Databases	PostgreSQL (Prisma), MongoDB (Mongoose), NeonDB
Auth	Clerk
Payments	Stripe
Messaging	Kafka
Repo Management	Turborepo + PNPM
Language	TypeScript
Infrastructure	Docker Compose (WIP)

💡 Key Learnings Showcased

✅ Real-world microservices communication using Kafka
✅ Handling different databases per service (polyglot persistence)
✅ Clean service isolation via Turborepo
✅ Seamless third-party API integration (Stripe, Clerk)
✅ Event-driven flow with async reliability

👨‍💻 Author

Mudit Kalra
Fullstack & Systems Design Enthusiast
Building scalable distributed systems with Node.js, Kafka, and Next.js

🌟 Project Status

🚧 In active development — evolving toward a fully distributed, event-driven e-commerce ecosystem.
⭐ Star this repo if you find the architecture inspiring!