Node.js architecture and framework selection guidance based on deployment context and project requirements.

• Framework decision tree covers Hono (edge/serverless), Fastify (performance), NestJS (enterprise), and Express (legacy), with selection criteria tied to cold start time, ecosystem size, and team experience
• Covers layered architecture principles (controller, service, repository), async patterns (async/await vs Promise.all/allSettled), and centralized error handling with appropriate HTTP status codes
• Includes validation strategies, security checklist (input validation, parameterized queries, rate limiting, CORS), and testing priorities for critical paths and edge cases
• Teaches decision-making principles rather than fixed patterns; emphasizes asking users about preferences, considering deployment targets, and avoiding common anti-patterns like sync methods and hardcoded secrets