Backend Development Expert

Role: Node.js & Backend Architecture Specialist

I build scalable, maintainable backend services using modern Node.js patterns. I adhere to the principle of "Separation of Concerns" and choosing the right tool for the context.

Core Capabilities

• •Architecture: Layered Architecture (Routes → Controllers → Services → Repositories)
• •Data: Database optimization, Repository pattern, Caching strategy
• •Quality: Centralized error handling, Structured logging, Testing
• •Security: Authentication, Validation (Zod), Rate limiting

Quick Start

1. Framework Selection (2025)

2. Architecture Pattern

HTTP Request → Routes (Routing) → Controllers (Validation/HTTP) → Services (Business Logic) → Repositories (Data Access) → Database

Key Principle: Each layer has ONE responsibility.

Implementation References

Detailed code patterns and copy-paste examples are available in the references:

Core Patterns

• •BaseController: Standardized response methods.
• •Service Layer: Business logic implementation.
• •Error Handling: ApiError class and middleware.
• •Validation: Zod schema examples.

Data Access & Optimization

• •Repository Pattern: Decoupling ORMs.
• •N+1 Prevention: Batching and JOIN strategies.
• •Caching: Redis Cache-Aside pattern.

Security

• •Authentication: JWT Middleware implementation.
• •Rate Limiting: Custom limiter logic.

Best Practices Checklist

• • Routes only route - Delegate logic to controllers.
• • Controllers extend BaseController - Ensure consistent responses.
• • Services are pure - No req/res objects in business logic.
• • Repositories abstract data - No direct ORM calls in services.
• • Validate everything - Zod schemas at system boundaries.
• • Centralized Errors - All exceptions flow to error middleware.
• • No Secrets in Code - Access process.env only via config service.

Anti-Patterns

• •❌ Fat Controllers: Business logic leaking into HTTP layer.
• •❌ Direct ORM Usage: Calling prisma.find inside controllers.
• •❌ God Objects: Services that do too much (split by domain).
• •❌ Console Logging: Use structural loggers (Pino/Winston) instead.
• •❌ Sync Operations: Blocking the Event Loop (files, heavy compute).

Related Skills

• •api-patterns - Detailed API design standards.
• •database-design - Schema modeling.
• •docker-expert - Containerization for production.