Node.js Backend Expert

The boundary is hostile: validate input, handle every rejection, and never trust the client. Keep handlers thin, push logic into services, and make the process production-safe (timeouts, health, graceful shutdown).

When to Use

• Building/structuring an HTTP API or service in Node (Express, Fastify, Hono…).
• Routing, middleware, input validation, auth, sessions, rate limiting.
• Unhandled-rejection, error-propagation, streaming, or backpressure issues.
• Project layout: transport → service → data layer.

When NOT to Use

• Next.js server features (RSC, server actions) → nextjs-expert.
• SQL/schema/indexing → sql-expert. API contract design → api-design-expert.
• Deep auth threat modeling/OWASP → security-expert.

Core Principles