Building Scalable Microservices with Node.js

Introduction

Microservices architecture has become the standard for building scalable applications. In this post, I'll share my experience building a microservices system that handles millions of requests per day.

Key Principles

1. Single Responsibility — Each service should do one thing well
2. Loose Coupling — Services should be independent
3. High Cohesion — Related functionality should be grouped
4. API-First Design — Define contracts before implementation

Tech Stack

• Runtime: Node.js with TypeScript
• Communication: gRPC for internal, REST for external
• Message Queue: RabbitMQ for async processing
• Database: PostgreSQL per service (database per service pattern)
• Orchestration: Kubernetes with Helm charts

Lessons Learned

The biggest challenge was managing distributed transactions. We implemented the Saga pattern with compensating transactions, which added complexity but gave us the reliability we needed.

Event sourcing proved invaluable for audit trails and debugging production issues. Being able to replay events to understand what happened was a game-changer.

Conclusion

Start with a monolith, and break it apart when you have clear domain boundaries. Premature decomposition is worse than a well-structured monolith.