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nestjs-best-practices▌

kadajett/agent-nestjs-skills · updated Apr 8, 2026

$npx skills add https://github.com/kadajett/agent-nestjs-skills --skill nestjs-best-practices
summary

40 NestJS best practices organized by priority across architecture, dependency injection, security, and performance.

  • ›Covers 10 rule categories from critical (architecture, DI) to low-medium (DevOps), each with specific, actionable patterns and anti-patterns
  • ›Includes rules for modules, controllers, services, error handling, authentication, database optimization, testing, and microservices
  • ›Each rule provides explanation, incorrect vs. correct code examples, and context for when to appl
skill.md

NestJS Best Practices

Comprehensive best practices guide for NestJS applications. Contains 40 rules across 10 categories, prioritized by impact to guide automated refactoring and code generation.

When to Apply

Reference these guidelines when:

  • Writing new NestJS modules, controllers, or services
  • Implementing authentication and authorization
  • Reviewing code for architecture and security issues
  • Refactoring existing NestJS codebases
  • Optimizing performance or database queries
  • Building microservices architectures

Rule Categories by Priority

Priority Category Impact Prefix
1 Architecture CRITICAL arch-
2 Dependency Injection CRITICAL di-
3 Error Handling HIGH error-
4 Security HIGH security-
5 Performance HIGH perf-
6 Testing MEDIUM-HIGH test-
7 Database & ORM MEDIUM-HIGH db-
8 API Design MEDIUM api-
9 Microservices MEDIUM micro-
10 DevOps & Deployment LOW-MEDIUM devops-

Quick Reference

1. Architecture (CRITICAL)

  • arch-avoid-circular-deps - Avoid circular module dependencies
  • arch-feature-modules - Organize by feature, not technical layer
  • arch-module-sharing - Proper module exports/imports, avoid duplicate providers
  • arch-single-responsibility - Focused services over "god services"
  • arch-use-repository-pattern - Abstract database logic for testability
  • arch-use-events - Event-driven architecture for decoupling

2. Dependency Injection (CRITICAL)

  • di-avoid-service-locator - Avoid service locator anti-pattern
  • di-interface-segregation - Interface Segregation Principle (ISP)
  • di-liskov-substitution - Liskov Substitution Principle (LSP)
  • di-prefer-constructor-injection - Constructor over property injection
  • di-scope-awareness - Understand singleton/request/transient scopes
  • di-use-interfaces-tokens - Use injection tokens for interfaces

3. Error Handling (HIGH)

  • error-use-exception-filters - Centralized exception handling
  • error-throw-http-exceptions - Use NestJS HTTP exceptions
  • error-handle-async-errors - Handle async errors properly

4. Security (HIGH)

  • security-auth-jwt - Secure JWT authentication
  • security-validate-all-input - Validate with class-validator
  • security-use-guards - Authentication and authorization guards
  • security-sanitize-output - Prevent XSS attacks
  • security-rate-limiting - Implement rate limiting

5. Performance (HIGH)

  • perf-async-hooks - Proper async lifecycle hooks
  • perf-use-caching - Implement caching strategies
  • perf-optimize-database - Optimize database queries
  • perf-lazy-loading - Lazy load modules for faster startup

6. Testing (MEDIUM-HIGH)

  • test-use-testing-module - Use NestJS testing utilities
  • test-e2e-supertest - E2E testing with Supertest
  • test-mock-external-services - Mock external dependencies

7. Database & ORM (MEDIUM-HIGH)

  • db-use-transactions - Transaction management
  • db-avoid-n-plus-one - Avoid N+1 query problems
  • db-use-migrations - Use migrations for schema changes

8. API Design (MEDIUM)

  • api-use-dto-serialization - DTO and response serialization
  • api-use-interceptors - Cross-cutting concerns
  • api-versioning - API versioning strategies
  • api-use-pipes - Input transformation with pipes

9. Microservices (MEDIUM)

  • micro-use-patterns - Message and event patterns
  • micro-use-health-checks - Health checks for orchestration
  • micro-use-queues - Background job processing

10. DevOps & Deployment (LOW-MEDIUM)

  • devops-use-config-module - Environment configuration
  • devops-use-logging - Structured logging
  • devops-graceful-shutdown - Zero-downtime deployments

How to Use

Read individual rule files for detailed explanations and code examples:

rules/arch-avoid-circular-deps.md
rules/security-validate-all-input.md
rules/_sections.md

Each rule file contains:

  • Brief explanation of why it matters
  • Incorrect code example with explanation
  • Correct code example with explanation
  • Additional context and references

Full Compiled Document

For the complete guide with all rules expanded: AGENTS.md