express-api-demo

A clean, minimal Express.js REST API — built as a demo project for the Technical Potpourri YouTube series on Gemini CLI Plan Mode.

No database required. All data lives in-memory so you can clone and run it instantly.

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🚀 Youtube Video

Youtube Video: Gemini CLI's New Plan Mode Changes Everything for Developers

Link: https://youtu.be/q-Qon0I7MS8

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🚀 Getting Started

git clone https://github.com/YOUR_USERNAME/express-api-demo.git
cd express-api-demo
npm install
npm run dev       # development (nodemon)
# or
npm start         # production

Server starts at http://localhost:3000

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📦 Project Structure

express-api-demo/
├── app.js                  ← Entry point, middleware & route registration
├── routes/
│   ├── users.js            ← CRUD routes for /api/users
│   └── products.js         ← CRUD routes for /api/products
├── data/
│   ├── users.js            ← In-memory users array
│   └── products.js         ← In-memory products array
├── middleware/
│   ├── logger.js           ← Request logger
│   └── errorHandler.js     ← Central error handler
├── package.json
└── .gitignore

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🔌 API Endpoints

Health Check

Method	Path	Description
GET	/	Server health check

Users — /api/users

Method	Path	Description
GET	/api/users	List all users
GET	/api/users?role=admin	Filter users by role
GET	/api/users/:id	Get a single user
POST	/api/users	Create a new user
PUT	/api/users/:id	Update an existing user
DELETE	/api/users/:id	Delete a user

Products — /api/products

Method	Path	Description
GET	/api/products	List all products
GET	/api/products?category=Electronics	Filter by category
GET	/api/products/:id	Get a single product
POST	/api/products	Create a new product
PUT	/api/products/:id	Update an existing product
DELETE	/api/products/:id	Delete a product

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🧪 Example Requests

# Get all users
curl http://localhost:3000/api/users

# Get a single user
curl http://localhost:3000/api/users/1

# Filter by role
curl http://localhost:3000/api/users?role=admin

# Create a user
curl -X POST http://localhost:3000/api/users \
  -H "Content-Type: application/json" \
  -d '{"name":"Eve Taylor","email":"eve@example.com","role":"user"}'

# Update a user
curl -X PUT http://localhost:3000/api/users/1 \
  -H "Content-Type: application/json" \
  -d '{"role":"superadmin"}'

# Delete a user
curl -X DELETE http://localhost:3000/api/users/2

# Get all products (Electronics only)
curl http://localhost:3000/api/products?category=Electronics

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🎬 Used In

This repo is the demo project for the Technical Potpourri video: "Gemini CLI Plan Mode — Think Before You Build"

Link: https://youtu.be/q-Qon0I7MS8

👉 Watch it at sudipta-deb.in or on the Technical Potpourri YouTube channel.

The video demonstrates how to use Gemini CLI Plan Mode to add rate limiting to this API — without the agent touching a single file until a full plan is reviewed and approved.

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📄 License

MIT

ExpressAPIDemoApplication