Web Builder

Builds websites and web apps — from idea to live deployment. Describe what you need and Web Builder writes the code, previews it on a live desktop, and pushes it to your server with HTTPS configured automatically.

## What it's good at

- **Website development** — corporate sites, product landing pages, portfolios, event pages
- **Form-based apps** — registration forms, membership sign-ups, surveys, with server-side validation and bot prevention
- **Live preview** — runs the app in a VNC desktop browser during development; you see it before it ships
- **Visual testing** — takes screenshots at multiple viewport sizes (desktop + mobile) to check responsive layout
- **SSH deployment** — pushes build artifacts to your server, starts a Docker container, and sets up NGINX with Let's Encrypt HTTPS
- **Project management** — one directory per project, a unified index, and status tracking (developing / live / archived)

## How it works

Web Builder uses a full desktop sandbox with SSH credentials injected. The stack is Next.js App Router + Tailwind CSS + TypeScript. Forms use Zod for server-side validation, SQLite for data storage, and SVG Captcha for bot prevention.

During development, Web Builder starts a local dev server and opens it in the VNC browser. It takes automated screenshots to verify layout, then iterates if anything looks off.

Once you're ready to deploy, it runs the build, pushes the output to your server via SSH, and configures NGINX + Docker + Let's Encrypt automatically. No manual server setup needed.

The sandbox is `longrunning` — it pauses when idle and resumes when you return. All project directories and configs are permanently stored in the workspace.

## How to write a good prompt

**Describe the site's purpose and structure.** "A company website with home, about us, services, and contact pages" gives Web Builder enough to scaffold immediately.

**Specify any forms and their requirements.** "An event registration form with phone number validation, CAPTCHA, and a confirmation email" covers the key constraints.

**Provide deployment details when ready.** Domain, server IP, and SSH credentials are needed to deploy. You can supply these at any point — Web Builder will ask if it needs them.

**Examples:**

> Build a company website: home page, about us, services, and contact form. Use a clean, modern design with navy and white.

> Create an event registration form for our annual conference. Collect name, email, company, and role. Include CAPTCHA and send a confirmation email.

> Build a membership sign-up page with phone verification and a payment placeholder.

> Deploy the current project to my server at 43.162.98.169. Domain: mysite.com. I'll paste the SSH key.

> Show me the current project status — what's live and what's still in development.

## Capabilities at a glance

| Capability | Details |
|------------|---------|
| Stack | Next.js App Router + Tailwind CSS + TypeScript |
| Forms | Zod validation, SQLite storage, SVG Captcha |
| Preview | VNC desktop + automated responsive screenshots |
| Deployment | SSH → Docker → NGINX → Let's Encrypt HTTPS |
| Project management | Per-project directories, unified index, status tracking |
| Sandbox | `claude-desktop-ssh` image, 4 GB RAM, 2 vCPUs, VNC + SSH enabled |
| Lifecycle | Long-running — pauses on idle (1 h), max 24 h per session |
| Workspace | Permanently stored — all project files and configs persist indefinitely |

## What's next

- [Applet Workshop](/docs/en-us/built-in-agents/applet) — for lightweight tools that don't need deployment
- [General Assistant](/docs/en-us/built-in-agents/general) — for custom backend logic or scripts outside a web project
- [AI Experts: Find the Right One](/docs/en-us/getting-started/ai-experts-intro) — see all built-in experts