How to Build a Full-Stack App in 10 Minutes

What We're Building

A todo app with a Node.js/Express backend, React frontend, and in-memory storage — built entirely using the AI Agent. Total time: under 10 minutes.

Step 1 — Create a Node.js Project (30s)

Go to your dashboard and click New Project → Node.js. Name it "Todo App". It opens in the editor immediately.

Step 2 — Let the Agent Build the Backend (3 min)

Click AI Agent in the sidebar and type:

> "Build an Express REST API with these routes: GET /api/todos, POST /api/todos, PUT /api/todos/:id, DELETE /api/todos/:id. Store todos in memory as an array. Each todo has id, text, and done fields. Add CORS headers so a React frontend on a different port can call it. Use port 3000."

Watch the agent create index.js, routes/todos.js, and configure CORS. When it's done, the preview shows the API is running.

Step 3 — Test the API (1 min)

Open the terminal and run:

curl http://localhost:3000/api/todos
# → []

curl -X POST http://localhost:3000/api/todos \
  -H "Content-Type: application/json" \
  -d '{"text":"Buy groceries"}'
# → {"id":"1","text":"Buy groceries","done":false}

Step 4 — Add the React Frontend (4 min)

Ask the agent:

> "Create a React frontend in a client/ folder. It should show the todo list, have an input to add todos, checkboxes to mark done, and a delete button. Use the API at /api. Style it cleanly with CSS — dark background, cards, smooth transitions."

The agent creates client/index.html, client/App.jsx, and client/style.css, then configures Express to serve the static files.

Step 5 — Deploy (30s)

Click Publish in the top-right. In 30 seconds your app is live at:

https://todo-app.spinini.com

Share that URL with anyone — it works on mobile, desktop, everywhere.

What Just Happened

In 10 minutes you:

Created a REST API with full CRUD
Built a React frontend that talks to it
Deployed both to a public URL with HTTPS

The AI Agent wrote every line of code. You described the outcome; it handled the implementation.

Going Further

Connect a real database (Postgres, SQLite)
Add user authentication
Set environment variables in Secrets
Connect your custom domain in Deploy settings