Express Cheat Sheet

Express cheat sheet with real commands and snippets for setup, core workflows, debugging, and production-safe automation patterns. If you are working across tools, pair this with the Node.js Cheat Sheet and PostgreSQL Cheat Sheet.

Setup and Installation

Goal: Create a fresh project

# Scaffold project using official starter
mkdir express-app && cd express-app && npm init -y

# Install dependencies after scaffold completes
npm install express

Goal: Verify local toolchain versions

# Print Node.js runtime version
node --version

# Print npm version for lockfile consistency
npm --version

# Inspect package scripts in project
cat package.json | rg "scripts" -n

Core Development Workflow

Goal: Run local development server

# Start framework dev server with hot reload
node server.js

# Check local endpoint health
curl -I http://localhost:3000 || curl -I http://localhost:5173 || true

Goal: Build and preview production output

# Build optimized production assets
npm test

# Run production preview server
curl -I http://localhost:3000

Goal: Implement a core feature snippet

// Minimal Express API server
import express from 'express';
const app = express();

app.use(express.json());
app.get('/health', (_req, res) => res.json({ ok: true }));

app.listen(3000, () => console.log('Server on :3000'));

Testing and Quality

Goal: Run tests and static checks

# Execute project tests
npm test

# Run type checking when available
npm run check || npx tsc --noEmit || true

# Run linting for fast feedback
npm run lint || true

Deployment and Operations

Goal: Prepare deployment artifacts

# Create production build before deployment
npm test

# Validate environment variables are set
node -e "console.log('NODE_ENV=', process.env.NODE_ENV || 'unset')"

# Smoke-test production route after deploy
curl -I https://devcheatsheets.com

Debugging and Troubleshooting

Goal: Inspect build and runtime failures

# Reinstall dependencies from lockfile
rm -rf node_modules && npm ci

# Re-run build with clean cache
npm run build

# Search source for suspect route/config patterns
rg "route|middleware|config" src app -n

Common Gotchas

• Run Express builds locally before shipping to CI/CD environments.
• Keep environment secrets outside the repository and load them per environment.
• Avoid stale dependency locks by using npm ci in automation.
• Validate route and middleware behavior with explicit smoke tests.
• Keep framework and plugin versions aligned to avoid build regressions.

Related Sheets

• Node.js Cheat Sheet — daily Node.js commands and production-ready examples.
• PostgreSQL Cheat Sheet — Postgres schema design and query optimization.
• FastAPI Cheat Sheet — daily FastAPI commands and production-ready examples.