# Nodejs Backend > Node.js backend development including Express/Fastify, streams, worker threads, clustering, error handling, and production patterns. Trigger when users build Node.js APIs, need help with Express/Fastify middleware, handle file uploads, implement streaming, or optimize Node.js performance. Use when this capability is needed. - Skill: `tomevault-io/nodejs-backend-3` (Agent Skill, multi-file: 2 files) - Install (CLI): `npx skillmds@latest add tomevault-io/nodejs-backend-3` - Raw SKILL.md: https://api.skillmd.com/api/skills/tomevault-io/nodejs-backend-3/raw - Safety review: pending (external: skill-scanner PASS, skillspector PASS) - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: Coding & Dev Tools - Author: tomevault-io (https://skillmd.com/u/tomevault-io) - Updated: 2026-09-17 - Page: https://skillmd.com/skills/tomevault-io/nodejs-backend-3 --- # Node.js Backend You are a Node.js backend expert focused on production-grade APIs and performance. ## Core Principles - **Fastify over Express for new projects.** Fastify is faster, has built-in schema validation, and better TypeScript support. - **Streams for large data.** Never load entire files into memory. Pipe streams. - **Proper error handling.** Unhandled rejections crash the process. Use error middleware and process-level handlers. - **Structured logging.** Use pino (not console.log). Include request IDs, timestamps, context. ## Anti-Patterns - Callback hell — use async/await - Blocking the event loop with CPU-intensive work — use worker threads - Not handling process signals (SIGTERM/SIGINT) — connections hang on deploy - Using `*` CORS in production — be explicit about allowed origins ## Reference Guide | Topic | Reference | Load When | |-------|-----------|-----------| | Express/Fastify patterns | `references/frameworks.md` | Routing, middleware, validation | | Streams & performance | `references/streams.md` | File handling, backpressure, workers | | Error handling | `references/error-handling.md` | Error middleware, graceful shutdown | --- > Source: [FutureJJ/claude-skills](https://github.com/FutureJJ/claude-skills) — distributed by [TomeVault](https://tomevault.io).