backend-dev-guidelines

Structure your Node.js Express backend using a layered architecture: Routes → Controllers → Services → Repositories → Database. This separation enforces zero cross-layer leakage, improving testability, maintainability, and predictable service behavior.

Use Zod for input validation in your Node.js microservices. Applying Zod-based validation within Express controllers ensures strict data integrity, preventing malformed requests from reaching your core business logic or Prisma database layer.

Centralize error handling and integrate Sentry in an Express app by implementing a BaseController. This pattern manages consistent response formatting and built-in Sentry monitoring to track exceptions across your Node.js microservices.

Configure Prisma through repository patterns and apply dependency injection (DI) to build testable service layers. This isolates database access, making your Node.js microservice components fully mockable and robust for testing.

Yes, this Node.js backend architecture supports unified configuration management through the unifiedConfig pattern. This ensures safe configuration loading and built-in Sentry observability across your Express microservices without leaking sensitive data.

Applying strict layered architecture to existing Express routes requires refactoring monolithic logic into Controllers, Services, and Repositories. This may introduce initial overhead but is necessary to achieve zero cross-layer leakage and long-term maintainability.