node-express

A set of coding rules for Node.js and Express.js backend applications. Node.js runs JavaScript on the server, while Express.js is a framework for building web servers and APIs.

In plain words
What is it for?
Use it when building or reviewing Express APIs, including routes, middleware, configuration, authentication, database access, migrations, transactions, and API documentation.
Why use it?
It provides consistent guidance for organizing projects, handling requests and errors, validating data, securing endpoints, and connecting to databases.

Cursor rule for Cursor

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add rules/mitas/cursor-rules/node-express
Clone the repo
git clone --depth 1 https://github.com/mitas/cursor-rules

Made for: Cursor.

Per session 423 This file is loaded in full into every session.
When invoked 423 The same file — it is already loaded in full.
Security scan A 0 findings. Scan, not verified.
Origin 86% copy Near-identical to another mod in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00423 $0.00423
Opus 5 $0.00211 $0.00211
Sonnet 5 $0.00085 $0.00085
Haiku 4.5 $0.00042 $0.00042

Measured yesterday against content hash fd5e837fe639, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

node-express scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured yesterday.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

Origin

This is a copy

86% identical to node-express — 8 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

.cursor/rules/node-express.mdc · 86 lines

What it actually says


description: Node.js and Express.js best practices for backend development globs: /.js, **/.ts, src//*.ts

Node.js and Express.js Best Practices

Project Structure

  • Use proper directory structure
  • Implement proper module organization
  • Use proper middleware organization
  • Keep routes organized by domain
  • Implement proper error handling
  • Use proper configuration management

Express Setup

  • Use proper middleware setup
  • Implement proper routing
  • Use proper error handling
  • Configure proper security middleware
  • Implement proper validation
  • Use proper static file serving

API Design

  • Use proper REST principles
  • Implement proper versioning
  • Use proper request validation
  • Handle errors properly
  • Implement proper response formats
  • Document APIs properly

Database Integration

  • Use proper ORM/ODM
  • Implement proper migrations
  • Use proper connection pooling
  • Implement proper transactions
  • Use proper query optimization
  • Handle database errors properly

Authentication

  • Implement proper JWT handling
  • Use proper password hashing
  • Implement proper session management
  • Use proper OAuth integration
  • Implement proper role-based access
  • Handle auth errors properly

Security

  • Use proper CORS setup
  • Implement proper rate limiting
  • Use proper security headers
  • Implement proper input validation
  • Use proper encryption
  • Handle security vulnerabilities

Performance

  • Use proper caching
  • Implement proper async operations
  • Use proper connection pooling
  • Implement proper logging
  • Use proper monitoring
  • Handle high traffic properly

Testing

  • Write proper unit tests
  • Implement proper integration tests
  • Use proper test runners
  • Implement proper mocking
  • Test error scenarios
  • Use proper test coverage

Deployment

  • Use proper Docker setup
  • Implement proper CI/CD
  • Use proper environment variables
  • Configure proper logging
  • Implement proper monitoring
  • Handle deployment errors

Best Practices

  • Follow Node.js best practices
  • Use proper async/await
  • Implement proper error handling
  • Use proper logging
  • Handle process signals properly
  • Document code properly
Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. yesterday First seen · 86 lines · 423 tokens per session scan A fd5e837fe639

Subscribe to this mod's changes

node-express is a cursor rule published in the GitHub repository mitas/cursor-rules (2 stars, last pushed 1y ago), licensed MIT. It adds 423 tokens to every session, about $0.0021 per session on Opus 5. A static security scan graded it A with 0 findings. It is 86% identical to node-express, differing in 8 lines, and is treated as a copy.