backend-dev-guidelines

Layered architecture separates routes, controllers, services, and repositories for clear concerns. Routes handle HTTP requests, controllers orchestrate logic, services contain business rules, and repositories manage data access. This pattern reduces bugs and improves maintainability across Express microservices.

Use Zod for schema-based input validation in Express routes. Zod parses and validates request data before it reaches controllers, catching invalid inputs early and providing consistent error messages across your Node.js backend.

Integrate Sentry for error tracking and Zod for input validation to catch issues early. Standardized error handling across routes, controllers, and services ensures consistent logging, debugging, and observability in TypeScript microservices.

Yes. The guidelines provide migration patterns to modernize legacy code by gradually adopting layered architecture, dependency injection, Prisma for data access, and unified configuration management while maintaining service stability.

Use unifiedConfig to centralize environment-based settings across Express microservices. This standardizes how services access database URLs, API keys, and feature flags, reducing configuration bugs and simplifying deployment across environments.

Test each layer—routes, controllers, services, repositories—independently using consistent patterns. This layered testing approach catches integration issues early and ensures reliable behavior in Node.js microservices without duplicating test logic.